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Toxicological information

Carcinogenicity

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Description of key information

- Several oral carcinogenic studies performed on rats and hamsters are available. These studies showed only an increased incidence of forestomach 
tumours. Such effects are not relevant for humans.
- No impact on tumour incidence were observed in mice and rabbits after PMP dermal long term exposure.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Link to relevant study records

Referenceopen allclose all

Endpoint:
carcinogenicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The test conditions and the results are sufficiently described, and in general in accordance with the EC and OECD test guidelines. However, few animals were used, and only one dose level was tested. The GLP are not mentioned.
Qualifier:
no guideline followed
Principles of method if other than guideline:
substance administered in diet to 30 rats for 2 years. The aim of the study is to show the inhibitory effects of phenolic compounds on development
of naturally occurring preneoplastic hepatocytic foci.
GLP compliance:
not specified
Species:
rat
Strain:
Fischer 344
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS:
- Species: rat 
- Strain: Fischer 344 
- Sex: male/female 
- Source: Charles River Japan, Atsugi, Japan
- Age at study initiation: 6 weeks
- Weight at study initiation: 100 g
- Fasting period before study: data not available
- Housing: 5 to plastic cage with wood chips for bedding
- Diet: ad libitum (Oriental MF basal diet)
- Water: ad libitum
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS:
- Temperature (°C): 22-24°C
- Humidity (%): 55% (+/- 10%)
- Air changes: more than 15 times/hr
- Photoperiod: 12hrs dark / 12hrs light

IN-LIFE DATES: data not available
Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Details on exposure:
ADMINISTRATION / EXPOSURE:
- Route of administration: oral: feed
- Diet preparation: once a month, and stored in the dark until use
- homogeneity and stability of test material: data not available

- Dose selection rationale: data not available
- Rationale for animal assignment: data not available

*** Details on exposure:
- Diet preparation         
> Rate of preparation of diet: once a month, stored in the dark         
> Mixing appropriate amounts with: Oriental MF basal diet          
> Storage temperature of food: no data
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
104 weeks
Frequency of treatment:
daily
Post exposure period:
none
Remarks:
Doses / Concentrations:
0 or 2% in diet, corresponding to 0 and 500 mg/kg bw/d (based on rat weight of 375g, according to REACH guidance document chap.R8)
Basis:
no data
No. of animals per sex per dose:
30
Control animals:
other: yes, plain diet
Positive control:
no
Observations and examinations performed and frequency:
- Cage side observations: No data
- Detailed clinical observations: No data
- Body weight: Yes (weekly for the first 14 weeks, then once every 4  weeks)
- Food consumption and compound intake: Yes (over a 2-day period before weighing)
- Water consumption and compound intake:  Yes (over a 2-day period before weighing)
- Ophtalmoscopic examination: No
- Haematology: No 
- Clinical chemistry: No
- Urinalysis: No 
- Neurobehavioural examination: No
Sacrifice and pathology:
- Gross pathology:  Yes 
- Histopathology:  Yes 
Rats becoming moribund and those found dead during the experiment were autopsied, and all surviving animals were killed under ether anesthesia  at the end of the week 104. All organs were removed, and the liver and kidneys were weighed and fixed in 10% buffered formalin solution. 
The stomach and esophagus were injected with formalin solution and later opened via an excision along the greater curvature.
Tissues were processed routinely for histopathological examination. Both early and terminally killed animals were included in the effective numbers
 for lesion development.
Tissues collected for histopathological examination: tongue, esophagus, stomach, colon, liver, pancrease, abdominal 
cavity, lung, kidneys, testes, uterus, brain, adrenal gland, mammary gland, thyroids, preputial gland, Zymbal's gland, clitorial gland, skin and forelimb.
Statistics:
Student's t-test and Fisher's exact test were used for statistical evaluation.
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
effects observed, treatment-related
Relevance of carcinogenic effects / potential:
In this study, only forestomach tumours were observed. These tumour lesions are not relevant for Humans.
Dose descriptor:
LOAEL
Effect level:
500 mg/kg bw/day
Sex:
male/female
Basis for effect level:
other: decreasing body weight and weight gain, increasing relative liver, kidney weight and hyperplasia in the glandular stomach
Remarks on result:
other:
Remarks:
Effect type: other: see basis for effect
Dose descriptor:
LOAEL
Effect level:
500 mg/kg bw/day
Sex:
male/female
Basis for effect level:
other: increasing tumour lesions in the forestomach
Remarks on result:
other: Effect type: carcinogenicity

- Clinical signs: no data

- mortality: no effects 

- Body weight and weight gain: 

At the end of the experiment, body weights of animals treated with PMP were significantly lower than those in the control group. 2% PMP in diet can be converted in 500 mg/kg bw/day for rats, based on an average rat weight of 375g.(according to REACH guidance document chap.R8)

Table 1: Final body weights

 Group     Sex   No. of rat Final body weight (g) 
 PMP   M  20

367 (+/- 44) **

   F  26

271 (+/- 27) **

 Control  M  24

439 (+/- 29)

   F  26

313 (+/- 34)


**: significantly different from control group at p < 0.01

- Food consumption and compound intake: Average food consumption was slightly lower in the treated animals than those if the control group.
- Water consumption and compound intake: Average water consumption was slightly lower in the treated animals than those if the control group.
- Organ weights: Relative liver and kidney weights of the animals treated  witth PMP showed a significant increase.

Table 2: Final organ weights

 group sex  liver (%)  kidney (%) 
 PMP  m

3.19 (+/- 0.93)*

0.87 (+/- 0.14) **

   f

2.67 (+/- 0.28) ** 

0.68 (+/- 0.08) **

 control  m

2.62 (+/- 0.46)

0.67 (+/- 0.05)

   f

2.39 (+/-0.44) 

0.62 (+/- 0.09)


*: p <0.05 ; **: p < 0.01

- Gross pathology: Multiples nodules or large masses were found in the forestomachs of animals treated with PMP. 

The tumours in the PMP-treated  groups were mostly located in the mid region, where ring-shaped ulceration was observed at early stages 

of treatment.
- Histopathology: The histopathological lesions in the forestomach were classified into hyperplasia, papilloma and squamous 

cell carcinoma  categories.

Table 3: Histopathological findings in the forestomach

 group sex  nb of  rats   incidence (%)         
   HP  atypical HP  P  SCC
 PMP  m  30  100**  67**  50**  77**
   f  30  100**  37**  23** 20* 
 control  m  30  0  0  3  0
   f  30  0  0  0  -


HP = Hyperplasia ; atypical HP = Atypical hyperplasia ; P = Papilloma ;  SCC = Squamous cell carcinoma
*: p <0.05 ; **: p < 0.01

Hyperplasia was found in all rats given PMP. Incidence of atypical hyperplasia was increased in rats treated with PMP. 

Significant increases  in the incidences of papillomas and squamous-cell-carcinoma were observed  in rats given PMP.

Table 4: Differentiation and invasive character of SCC in the forestomach of rats treated with PMP

 sex  nb of rats  nb of SCC  differenciation (%)        invasion (%)      
       well  mod.  poor  I  II  III
 m  30  35  37  29  34  57  9  34
 f  30  6  50  50  0  67  0  33


SCC associated with PMP were predominantly moderately and poorly differentiated types. 

Many animals had a high grade of invasion (grade  III: direct invasion of the abdominal cavity or adjacent organs such as  

the liver, pancreas or glandular stomach, or dissemination to the abdominal cavity).

No significant changes were observed in the glandular stomach (see Table  5).

Table 5: Histopathological findings in the glandular stomach

 group sex  nb of rats  incidence (%)          
       SH  A  AC  S
 PMP  M  30  13  3  0  0
 PMP  F  30  7  0  0  0
 CONTROL  M  30  0  0  0  0
 CONTROL  F  30  0  0  0  0


SH = Submucosal hyperplasia ; A = Adenoma ; AC = Adenocarcinoma ; S =  Sarcoma

No significant alteration in tumorous lesions was found in any organs other than stomach.

Conclusions:
Based on this study, a LOAEL of 500 mg/kg bw/d were identified for general effects (decreasing body weight and weight gain,
increasing relative liver, kidney weight and hyperplasia in the glandular stomach).
PMP induced a significant increase in the incidence of papillomas and carcinomas only in forestomach. (not relevant for Humans)
Therefore a LOAEL of 500 mg/kg bw/d was identified for this effect.


Executive summary:

In a carcinogenicity study, PMP was administered to 30 Fisher 344 rats/sex/dose in diet at dose levels of 0,2% (~500 mg/kg bw/day) for 104 weeks.

The experiment clearly demonstrated only forestomach carcinogenicity for PMP, such effetc is not relevant for humans.

Males were more susceptible than females to induction of forestomach tumours.

Dosing was considered adequate based on the decrease in body weight in the treated animals (however only one dose level was tested). Forestomach carcinogenicity was already shown for the phenolic compounds BHA, caffeic acid, sesamol in the same laboratory in 2-year experiments at the same dose level as PMP. The carcinogenicity of PMP is the strongest among the phenolic compounds so far examined,

as evaluated by the incidenced of squamous-cell-carcinomas (BHA 17-35%, caffeic acid 57%, sesamol 31 in male F344 rats).

This carcinogenicity study in the rat is acceptable, and satisfies EC and OCDE guideline requirements for a carcinogenicity study, even if few

animals were used and only one dose level tested.

Endpoint:
carcinogenicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
This carcinogenicity study in the rat is acceptable (test conditions and results sufficiently described), even if it does not completely satisfy the EU and OECD guidelines (few numbers of animals, only one dose tested, only 51 weeks of treatment). The GLP are not mentioned.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Substance administered to male rats in diet at dose level of 0 or 1.5 % for 51 weeks
GLP compliance:
no
Species:
rat
Strain:
Fischer 344
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS:
- Source: Charles River Japan, Inc., Atsugi, Japan.
- Age at study initiation: 7 weeks old
- Weight at study initiation: data not available
- Fasting period before study: data not available
- Housing: 5 animals to a plastic cage
- Diet: ad libitum (Oriental MF basal diet)
- Water: ad libitum
- Acclimation period: data not available

ENVIRONMENTAL CONDITIONS:
- Temperature: 22-24°C (air-conditioned room)
- Humidity (%): data not available
- Air changes (per hr): data not available
- Photoperiod: 12h light/dark cycles

IN-LIFE DATES: data not available
Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Analytical verification of doses or concentrations:
not specified
Details on analytical verification of doses or concentrations:
No reduction in effective concentration of PMP was observed after storage of diets either in the dark for 3 weeks or in glass food container for 
3 days at room temperature.
Duration of treatment / exposure:
51 weeks
Frequency of treatment:
daily
Post exposure period:
none
Remarks:
Doses / Concentrations:
0 or 1.5% in diet, corresponding to ca. 375 mg/kg bw/d (based on a rat weight of 375g, according to technical guidance document of REACH chap R8)
Basis:
no data
No. of animals per sex per dose:
15
Control animals:
other: yes, plain diet
Details on study design:
- Diet preparation                 
> Storage temperature of food: in the dark for 3 weeks or in glass food container for 3 days at room temperature


- Dose selection rationale: chosen based on a previous experiment done in hamsters (see Hirose M et al, 1986)
- Rationale for animal assignment: randomly
- Rationale for selecting satellite groups: no
- Post-exposure recovery period in satellite groups: not applicable
Positive control:
no
Observations and examinations performed and frequency:
- Cage side observations: No data
- Detailed clinical observations: No data
- Body weight: Yes (once every 2-4 weeks)
- Food consumption and compound intake: No data 
- Food efficiency: No data
- Ophtalmoscopic examination: No 
- Haematology:  No 
- Clinical chemistry: No 
- Urinalysis: No 
- Neurobehavioural examination: No data
Sacrifice and pathology:
- Gross pathology:  Yes 
- Histopathology:  Yes 
Rats becoming moribund were sacrificed for autopsy, and surviving animals were killed under ether anesthesia. The stomach, esophagus, liver, 
kidneys, and intestines were removed, and liver and kidneys were weighed and fixed in 10% buffered formalin solution. Formalin was injected in 
the esophagus, stomach, and intestines and later they were opened via an excision along the greater curvature. After fixation, 6 sections each 
were cut from the anterior and posterior walls of the forestomach and glandular stomach. Tissues were processed in the usual ways for 
histopathological examination.
Other examinations:
Other groups of 20 animals were given 150 mg/kg bw of MNNG (CAS 70-25-7) in saline by stomach tube. From 1 week later, these rats were 
given Oriental MF powdered diet containing 1.5% PMP or basal diet alone for 51 weeks. The final body weight of animals given MNNG+PMP were 
significantly lower than those treated with MNNG alone (P < 0.001). However liver and kidney weights were significantly higher than the control.
Grossly, animals treated with MNNG+PMP had large ulcers parallel to the  limiting ridge with only a few tumours developing on the adjoining mucosa. Hyperplasia was induced in the forestomach of all animals treated with MNNG+PMP. The incidence of carcinoma in-situ was significantly lower in 
 rats given MNNG+PMP (5.5%) than in the control group (57.9%). SCC were not induced in rats treated with MNNG+PMP, but the value was not  
significantly different from that of the control group. Leiomyosarcoma was induced in 1 rat. Adenomatous hyperplasia or adenocarcinoma were 
not observed in the glandular stomach after treatment with MNNG+PMP. Tumours were not observed in the other organs examined such as the  
esophagus and intestines.
Statistics:
Student's t test and Chi² test statistics were used for the evaluation of the data.
Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed
Dose descriptor:
LOAEL
Effect level:
375 mg/kg bw/day
Sex:
male
Basis for effect level:
other: increasing of liver and kidney weight, forestomach hyperplasia
Remarks on result:
other:
Remarks:
Effect type: other: see basis for effect level

- Organ weights:

Table 1: Final liver and kidney weight

 group  No. of rats  body weight (g)  liver weight (g/100 g bw)  kidney weight (g/100 g bw)
 0%  10

427 +/- 30                

2.59 +/- 0.07  0.52 +/- 0.02
 1.5%  15  405 +/- 14     2.64 +/- 0.10*   0.64 +/- 0.04*


*: P < 0.001

Liver and kidney weights were significantly higher in animals treated with PMP, when compared to the corresponding control group.
 
- Histopathology: non-neoplastic: 

Table 2: Histological changes in the forestomach

 group  no. of rats with lesions (%)         
   HP C (in- situ)   SCC
 0%  0  0  0  0
 1.5%  100*  6.7  0  0


HP = Hyperplasia ; P = Papilloma ; C = Carcinoma ; SCC = Squamous cell carcinoma
*: P < 0.001

Forestomach hyperplasia was induced in all animals treated with PMP.

Table 3: Histological changes in the glandular stomach

 group  No. of rats with lesions (%)         
   fundic region     pyloric region   
   Adenomatous  hyperplasia  Adeno-  carcinoma    Adenomatous hyperplasia   Adeno- carcinoma
 0%  0  0  0
 1.5%  0  0  0 0


Adenomatous hyperplasia or adenocarcinoma were not observed in the glandular stomach after treatment with PMP.

Tumours were not observed in the other organs examined such as the esophagus and intestines.

Conclusions:
No change in tumour incidence was noted in this study.However, a LOAEL of 375 mg/kg bw/d can be identify for general toxicity (increasing of liver and kidney weight, forestomach hyperplasia).
Executive summary:

In a carcinogenicity study, PMP was administered to male F344 rats (15 animals/dose) in diet at dose levels of 0 or 1.5% (0 or ~ 375 mg/kg bw/day) for 51 weeks. No effects were observed in the mortality or the body weight gain of the treated animals. Liver and kidney weights were significantly higher in animals treated with PMP, when compared to the corresponding control group. PMP induced forestomach hyperplasia in all animals tested. At the dose tested, there was not a treatment related increase in tumor incidence when compared to controls.

This carcinogenicity study in the rat is acceptable; test conditions and results sufficiently described, even if it does not completely satisfy the EU and OECD guidelines (few number of animals, only one dose tested, only 51 weeks treatment). The GLP are not mentioned.

Endpoint:
carcinogenicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: This carcinogenicity study in the rat is acceptable (test conditions and results sufficiently described), even if it does not completely satisfy the EU and OECD guidelines (few numbers of animals, only one dose tested). The GLP are not mentioned.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Substance administered daily in diet at dose level of 0 or 0.4 % (corresponding to ca. 0 or 100 mg/kg bw/d) to male rats, for 2 years.
GLP compliance:
not specified
Species:
rat
Strain:
Fischer 344
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS:
- Source: Charles River Japan Inc. (Kanagawa Japan)
- Age at study initiation: 6 weeks old
- Weight at study initiation: data not available
- Fasting period before study: data not available
- Housing: 5 to a plastic cage with wood chips for bedding
- Diet: ad libitum (Oriental MF powdered basal diet
- Water: tap water ad libitum
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS:
- Temperature: 24°C (+/- 2°C)
- Humidity (%): data not available
- Air changes (per hr): data not available
- Photoperiod: 12h light/dark cycles

IN-LIFE DATES: data not available
Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
104 weeks
Frequency of treatment:
daily
Post exposure period:
none
Remarks:
Doses / Concentrations:
0 or 0.4% in diet, corresponding to ca. 100 mg/kg bw/d (based on a rat weight of 375g, according to technical guidance document of REACH, chap.R8)
Basis:
no data
No. of animals per sex per dose:
30-31 males
Control animals:
other: yes, plain diet
Details on study design:
- Preparation of dosing solutions: no data available
- Diet preparation: no data available

- Dose selection rationale: data not available
- Rationale for animal assignment (if not random): data not available
- Rationale for selecting satellite groups: data not available
- Post-exposure recovery period in satellite groups: data not available
Positive control:
no
Observations and examinations performed and frequency:
- Cage side observations:  No data
- Detailed clinical observations:  mortality
- Body weight: Yes, once every 1-4 weeks
- Food consumption and compound intake: No data 
- Food efficiency: No data
- Ophtalmoscopic examination: No 
- Haematology: No 
- Clinical chemistry:  No 
- Urinalysis: No
- Neurobehavioural examination: No data
Sacrifice and pathology:
- Gross pathology:  No data
- Histopathology:  Yes 
All survivor were killed under ether anesthesia at the end of week 104, and subjected to complete autopsy. Animals that survived until the end of  
the experiment were included in the effective numbers. Tissues were processed routinely for hematoxylin and eosin staining.
Other examinations:
no data
Statistics:
no data
Clinical signs:
not specified
Mortality:
not specified
Body weight and weight changes:
effects observed, treatment-related
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
not specified
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed
Dose descriptor:
LOAEL
Effect level:
100 mg/kg bw/day
Sex:
male
Basis for effect level:
other: decreasing body weight and increasing forestomach hyperplasia
Remarks on result:
other:
Remarks:
Effect type: other: see basis for effect

- Body weight and weight gain: 

table 1: Final body weights

 group  No. of rats body weight (g)
 0%  28 444 +/- 38 
 0.4%  26 396 +/- 25 (**)

          
**: P < 0.01 (significantly different vs basal diet group values)

Final body weights of rats treated with PMP were lower than the control rats.

- Organ weights: No effects were noted on the relative liver and kidney weights of rats treated with PMP.

- Histopathology: non-neoplastic: 

Table 2: Histopathological findings in the forestomach

 group  PN hyperplasia (%)  multiplicity (No./slide)  papilloma (%)   multiplicity (No./slide)  carcinoma (%)
0%   4  0.08 +/- 0.39   0  -  0
0.4%  31*  0.31 +/- 0.46  12  0.19 +/- 0.62   0


*: P < 0.05

Table 3: Histopathological findings in the glandular stomach

group submucosal hyperplasia (%)  multiplicity (No./slide) adenoma (%)   multiplicity (No./slide)  
0%  0  - 0  -
0.4% 0 - 0  -   


PMP increased significantly the incidence of forestomach papillar or nodular (PN) hyperplasia, as compared with the basal diet. 

Slightly increased incidences (not significant) of forestomach papillomas were found in the PMP group. 

No effects were noted in the glandular stomach.  No significant alteration in the incidences of neoplastic lesions was found in the esophagus, 

liver or kidneys.

Conclusions:
No significant change in tumour incidence were seen in this study. PMP induced only a slight and no significant increase of forestomach papillomas indence. A LOAEL of 100 mg/kg bw/d was establisched for general toxicity (decreasing body weight and increasing forestomach hyperplasia).
Executive summary:

In a carcinogenicity study, PMP was administered to male F344 rats (30-31 animals/dose) in diet at dose level of 0 or 0.4% (0 or ~ 100 mg/kg bw/day) for 104 weeks. Final body weights of rats treated with PMP were lower than the control rats.

PMP increased significantly the incidence of forestomach papillar or nodular (PN) hyperplasia, as compared with the basal diet. Slightly increased incidences (not significant) of forestomach papillomas were found in the PMP group.

At the dose tested, there was not a treatment related increase in tumor incidence when compared to controls. This carcinogenicity study in the rat is acceptable (test conditions and results sufficiently described), even if it does not completely satisfy the EU and OECD guidelines (few number of animals, only one dose tested).

Endpoint:
carcinogenicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The test conditions and results are sufficiently described. The experiment is interesting and reliable for the assessment.
GLP compliance:
not specified
Species:
rat
Strain:
Fischer 344
Sex:
male
Route of administration:
oral: feed
Duration of treatment / exposure:
104 weeks
Frequency of treatment:
daily
Post exposure period:
none
Remarks:
Doses / Concentrations:
0, 2% in diet, corresponding to ca. 0 or 500 mg/kg bw/d (based on rat weight of 375g, according to technical guidance document on REACH, chap.R8)
Basis:
no data
No. of animals per sex per dose:
no data
Control animals:
other: yes, plain diet
Statistics:
the significances of intergroup differences in numerical data obtained for enzyme-altered foci were assessed using the 2-sided Student's t-test. Insufficient homogeneity of variance was corrected with respect to the degree of freedom according to the method of Welch.
Dose descriptor:
NOAEL
Remarks on result:
not determinable
Remarks:
no NOAEL identified

MEDIUM-TERM LIVER BIOASSAY
Inhibitory effects on foci development were obvious (ca. 50%, p < 0.01) with PMP (and all other phenolic compounds examined).

LONG-TERM FEEDING STUDY
No statistically significant increase in liver to body weights ratio was noted (see free text Remark).
Hepatocytic tumour incidences were low in both controls and treated animals, and no intergroup differences were found.
Treated/control proportional values for the average numbers and areas, respectively, of GST-P+ hepatocytic foci were 49 and 49%. 

Inhibitory effects on GST-P+ foci development were apparent with PMP (and all other phenolic compounds examined).
Quantitative values for TGFa+ foci in aged rats, with or without  administration of PMP, were low (0%).

Conclusions:
In the present investigation, PMP clearly inhibited the development of naturally occuring GST-P+ hepatocytic foci in aged rats, as predicted
from the results of medium-term liver bioassays (Ito test).
However, chemopreventive effects on liver carcinogenesis could not be demonstrated in the previous long-term study, since the incidences of
spontaneous liver tumours were too low to allow assessment of inhibition.
Endpoint:
carcinogenicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Even if the study is not fully in accordance with the EU guideline (few animals, only one dose, only 20-week exposure, only male hamsters), the assay is sufficiently described and acceptable for the assessment.
Qualifier:
no guideline followed
Principles of method if other than guideline:
substance administered to male hamsters in diet at dose level of 0 or 1.5 %  for 20 weeks
GLP compliance:
not specified
Species:
hamster, Syrian
Strain:
not specified
Sex:
male
Details on test animals and environmental conditions:
- Source: Kagawa Tsuda Animal Co., Kagawa, Japan
- Age at study initiation: 7 weeks old
- Weight at study initiation: data not available
- Fasting period before study: data not available
- Housing: 5 to a plastic cage
- Diet: ad libitum (Oriental MF powdered basal diet)
- Water: ad libitum
- Acclimation period: data not available

ENVIRONMENTAL CONDITIONS:
- Temperature: 24°C (+/- 2°C)
- Humidity: data not available
- Air changes: data not available (air-conditioned room)
- Photoperiod: 12h light/dark cycle 

IN-LIFE DATES: data not available
Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
20 weeks
Frequency of treatment:
daily
Post exposure period:
none
Remarks:
Doses / Concentrations:
0 and 1.5% in diet, corresponding to ca. 225 mg/kg bw/d (based on a hamster weight of 160 g, according to technical guidance document on REACH chap.R8)
Basis:
no data
No. of animals per sex per dose:
15
Control animals:
other: yes, plain diet
Details on study design:
- Preparation of dosing solutions: no data
- Diet preparation: no data
- Dose selection rationale: based on LD50 of rats, and animals were given approximately a quarter of LD50 in this experiment
- Rationale for animal assignment: data not available
Positive control:
no
Observations and examinations performed and frequency:
- Cage side observations: No data
- Detailed clinical observations: No data
- Body weight: Yes (at the end of the exposure period)
- Food consumption and compound intake: No data 
- Food efficiency: No data
- Ophtalmoscopic examination:  No 
- Haematology: No 
- Clinical chemistry: No 
- Urinalysis: No 
- Neurobehavioural examination:  No data
Sacrifice and pathology:
- Gross pathology: Yes (all animals, at terminal sacrifice)
- Histopathology: Yes (all animals, at terminal sacrifice) 
Animals were killed with ether and their liver, kidneys, cheek pouch, stomach, esophagus, lung, pancreas, and urinary bladder were removed. 
The liver and kidneys were weighed and organs were fixed in 10% buffered formalin solution. 5 sections each were cut from the anterior and 
posterior walls of the forestomach, 2 from the glandular stomach, and 4 from the urinary bladder.
Tissues were processed in the usual ways for histopathological and autoradiographic examinations.
Other examinations:
- Autoradiographic examination: 3 hamsters in each group received an i.p. injection of 0.1 mCi/100 g body weight of 
[methyl-3H]thymidine (1 mCi/mL) 1h before killing. 5 µm sections were coated with Fuji ET-2F emulsion, stored in the dark at 4°C for 7 days, 
and then developed, fixed and stained lightly. Counts were made on 4000 cells of urinary bladder epithelium, 3000 cells of pyloric gland epithelium
and 2000 basal cells for the forestomach epithelium. Labelling index was expressed as number of labelled cells per 100 cells.
Statistics:
no data available
Body weight and weight changes:
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed
Dose descriptor:
LOAEL
Effect level:
225 mg/kg bw/day
Sex:
male
Basis for effect level:
other: significant hyperplasia in forestomach and pyloric region
Remarks on result:
other:
Remarks:
Effect type: other: see basis for effect

- Body weight and weight gain: 

Table 1: Average final body and liver weights

 group  No. hamsters  body weight (g)  liver weight (g/100 g bw)
 0%  15

203 +/- 23

3.8 +/- 0.4

 1.5%  15

205 +/- 16

4.0 +/- 0.3


No significant effects were noted in the final body weights and liver weights in the treated animals.

- Gross pathology: 
Prominent thickening of the forestomach epithelium with a keratin-like white substance was observed. This epithelial change was observed in the 

 posterior and anterior walls along the lesser curvature and adjacent to the esophagus.

- Histopathology: non-neoplastic: 

Table 2: Histological changes induced in the forestomach

 group  no. of hmaster (%) with:         
   mild HP  moderate HP  severe HP  papillomatous lesions
 0%  46.7  6.7  0  0
 1.5%  100***  73.3***  20  0


HP = Hyperplasia ; *** = p < 0.001

Hamsters given PMP showed higher incidences of mild hyperplasia (<0.1 mm) and moderate hyperplasia (0.1-0.5 mm) in the forestomach than the control group.
Inflammatory cell infiltration into the mucosa or submucosa, scars of  ulcers, or regenerative hyperplasia with slight atypia of cells were found in 

the pyloric regions of the stomach.
No abnormal findings were observed in other organs examined.

- Other findings: 
AUTORADIOGRAPHIC STUDY:


Table 3: Labelling index (3 animals per group)

 group  labelling index      
   forestomach  pyloric region  urinalysis bladder
 0%

12.5 +/- 4.7

7.3 +/- 1.9 

0.08 +/- 0.14

 1.5%

22.3 +/- 1.1*

16.4 +/- 4.4*

0.21 +/- 0.10


*: P < 0.05

Significant increase in the labelling index was found in the group  treated with PMP.

Conclusions:
No tumorous lesions were seen in the forestomach. A LOAEL of 225 mg/kg bw/d was identified for hyperplasia of forestomach and pyloric region of stomach.
Executive summary:

In a carcinogenicity study, PMP was administered to male Syrian hamsters (15 animals/dose) in diet at dose levels of 0 and 1.5% PMP (0 and ~ 225 mg/kg bw/day) for 20 weeks. PMP induced hyperplasia in the forestomach, but no tumorous lesions. The labelling index in the forestomach epithelium and glandular stomach were significantly increased by addition to the diet of PMP. PMP induced epithelial damage and regenerative hyperplasia of the pyloric region. No histopathological lesions were observed in the urinary bladder epithelium. These findings indicate that PMP may act as promotor in two-stage forestomach carcinogenesis. This carcinogenicity study in the hamster is acceptable, even if it is not fully in accordance with EU guidelines (few animals, only one dose, only 20 week exposure).

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Study duration:
chronic
Species:
other: several species
Quality of whole database:
Studies well described.

Carcinogenicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via dermal route

Link to relevant study records

Referenceopen allclose all

Endpoint:
carcinogenicity: dermal
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study is sufficiently described and the test conditions are acceptable for the assessment.
Reason / purpose:
reference to same study
Qualifier:
no guideline followed
Principles of method if other than guideline:
cutaneous application on skin female mice twice a week for 120 weeks
GLP compliance:
no
Species:
mouse
Strain:
Swiss
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS:
- Source: Eppley colony
- Age at study initiation: 7 weeks old
- Weight at study initiation: ca. 29 g
- Fasting period before study: data not available
- Housing: 10 per group in plastic cages on commercial bedding  (San-i-cel, Paxton Processing Co., Inc., Paxton, Ill.)
- Diet: ad libitum (Wayne, Allied Mills, Chicago, Ill.)
- Water: tap ad libitum
- Acclimation period: data not available

ENVIRONMENTAL CONDITIONS:
- Temperature (°C): data not available
- Humidity (%): data not available
- Air changes (per hr): data not available
- Photoperiod (hrs dark / hrs light): data not available

IN-LIFE DATES: data not available
Route of administration:
dermal
Vehicle:
other: acetone or methanol
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
lifetime (up to 120 weeks)
Frequency of treatment:
twice a week
Post exposure period:
none
Remarks:
Doses / Concentrations:
5 and 10% in acetone or methanol
Basis:
no data
No. of animals per sex per dose:
50 per group
Control animals:
yes, concurrent no treatment
Details on study design:
- Test site: Area of exposure: on the dorsal skin between the shoulder  blades (shaved regularly), 1-inch square area
- Removal of test substance:         
> Washing (if done):  no data         
> Time after start of exposure: no data

- Test material:         
> Amount(s) applied: 0.02 mL         
> Concentration (if solution): 10 and 5 % in acetone or methanol
Positive control:
yes (40 mice) with DMBA (7,12-dimethylbenz[α]anthracene)
Observations and examinations performed and frequency:
- Cage side observations:  No data
- Detailed clinical observations:  No data
- Dermal irritation: No data
- Body weight: Yes (once every 10 weeks)
- Food efficiency: No data
- Ophtalmoscopic examination: No data
- Haematology:  No data
- Clinical chemistry:  No data
- Urinalysis: No data
- Neurobehavioural examination:  No data
Sacrifice and pathology:
- Gross pathology:  Yes
- Histopathology:  Yes 
Complete autopsies were performed on all animals. Skin samples, grossly observed tumors and other lesions of the lungs, liver, kidneys, ETC, 
from all the animals were studied histologically. Observation of tumor number and type of tumour.
Other examinations:
no data
Statistics:
The statistical significance of the results was evaluated using the method of ARMITAGE (1971).
Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Histopathological findings: neoplastic:
no effects observed
Details on results:
A significant decrease in the survival rates of mice directly attribuable to PMP under testing was not observed.
Their weights also remained comparable throughout their lifespans. No statistically significant difference in number of tumours between 
treated groups and the controls was observed. In DMBA-treated mice, treatment caused deterioration of health and led to the early death 
of the animals. 
The number of skin tumours in  DMBA-treated animals was significant and papillomas, squamous cell carcinomas and keratoacanthomas were seen,  indicating the sensitivity of Swiss mice to percutaneous carcinogen application.
No other information are available.
Dose descriptor:
NOAEL
Effect level:
> 10 other: % in vehicle
Sex:
female
Basis for effect level:
other: no effects on clinical signs, mortality, body weight, weight gain and tumor incidence
Remarks on result:
other: Effect type: carcinogenicity
Conclusions:
In this study, PMP did not induce any changes in tumour incidence in mice after cutaneous application.
Executive summary:

In a carcinogenicity study, 4-hydroxyanisole was administered to 50 female Swiss mice per dose by cutaneous route at dose levels of 5 and 10 % for lifetime (up to 120 weeks). A significant decrease in the survival rates of mice directly attribuable to PMP under testing was not observed. Their weights also remained comparable throughout their lifespans. No statistically significant difference in number of tumours between treated groups and the controls was observed. At the doses tested, there was not a treatment related increase in tumor incidence when compared to controls.

Based on this study a NOAEL is > 10% in vehicle for no effects on mortality, body weight and tumor incidence.

This carcinogenicity study in the mice is acceptable, even if it does not satisfy the guideline requirement for a carcinogenicity study OECD 451 in mice. (study in females only, from 7 week old, 2 doses only tested, not enough data on clinical examination)

Endpoint:
carcinogenicity: dermal
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study is sufficiently described and the test conditions are acceptable for the assessment.
Reason / purpose:
reference to same study
Qualifier:
no guideline followed
Principles of method if other than guideline:
cutaneous application to the interior ear of rabbits twice a week for 90 weeks
GLP compliance:
not specified
Species:
rabbit
Strain:
other: New Zealand
Sex:
male/female
Details on test animals and environmental conditions:
ENVIRONMENTAL CONDITIONS:
- Temperature (°C): data not available
- Humidity (%): data not available
- Air changes (per hr): data not available
- Photoperiod (hrs dark / hrs light): data not available

IN-LIFE DATES: data not available
Route of administration:
dermal
Vehicle:
other: acetone or methanol
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
lifetime (up to 90 weeks)
Frequency of treatment:
twice a week
Post exposure period:
none
Remarks:
Doses / Concentrations:
5 and 10% in acetone or methanol
Basis:
no data
No. of animals per sex per dose:
5 per group
Control animals:
yes, concurrent no treatment
Details on study design:
- Test site: Area of exposure: 0.02 mL applied to interior left ear (no other information available)
- Analytical verification of doses or concentrations: no data
- Removal of test substance:         
> Washing (if done):  no data         
> Time after start of exposure: no data

- Test material:         
> Amount(s) applied: 0.02 mL         
> Concentration (if solution): 10 and 5 % in acetone or methanol
Positive control:
yes, treated with DMBA(7,12-dimethylbenz[α]anthracene)
Observations and examinations performed and frequency:
- Cage side observations: No data
- Detailed clinical observations: No data
- Dermal irritation (if dermal study): No data
- Body weight: No
- Ophtalmoscopic examination:  No data
- Haematology:  No data
- Clinical chemistry: No data
- Urinalysis: No data
- Neurobehavioural examination:  No data
- mortality: yes
Observation of tumour number and type of tumour.
Sacrifice and pathology:
- Gross pathology:  Yes 
- Histopathology:  Yes 
Complete autopsies were performed on all animals. Skin samples, grossly  observed tumors and other lesions of the lungs, liver, kidneys, etc, 
from  all the animals were studied histologically.
Other examinations:
no data
Statistics:
The statistical significance of the results was evaluated using the method of ARMITAGE (1971).
Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Histopathological findings: neoplastic:
no effects observed
Details on results:
A significant decrease in the survival rates of rabbits directly attribuable to PMP under testing was not observed.
Their weights also remained comparable throughout their lifespans. No statistically significant difference in number of tumours between  
treated groups and the controls was observed (none were observed).
The positive DMBA-treated control was terminated at 50 weeks for morphological analysis ; animals that died before this time succumbed to 
diseases (mainly pneumonia) apparently unrelated to treatment.
Dose descriptor:
NOAEL
Effect level:
> 10 other: % in vehicle
Sex:
male/female
Basis for effect level:
other: no effects on survival rate, body weight or tumor incidence
Remarks on result:
other: Effect type: carcinogenicity
Conclusions:
No tumours were observed in rabbit treated group after PMP application in ear.
Executive summary:

In a carcinogenicity study, 4-hydroxyanisole was administered to 5 New Zealand rabbits per group by cutaneous application in ear at dose levels of 5 and 10 % in vehicle for lifetime, up to 90 weeks. A significant decrease in the survival rates of rabbits directly attribuable to PMP under testing was not observed. Their weights also remained comparable throughout their lifespans. No statistically significant difference in number of tumours between treated groups and the controls was observed (none were observed).

At the doses tested, there was not a treatment related increase in tumor incidence when compared to controls. This carcinogenicity study in the rabbit is acceptable, even it does not satisfy guideline requirement for a carcinogenicity study OECD 451 in rabbit. (rabbit of 8 weeks old, 2 doses only tested, not enough data on clinical examination).

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Study duration:
chronic
Species:
other: mouse and rabbit
Quality of whole database:
Study well described.

Additional information

Oral route: 5 studies are referenced in this section for carcinogenicity assays by oral route, PMP introducing in feed:

- Hagiwara et al., 1996 (a) and Asakawa et al., 1994, reliability 2:

In these carcinogenicity studies, PMP was administered to 30 Fisher 344 rats/ sex/ dose in diet at dose levels of 0 or 2% (equivalent to 0 and 500 mg/kg bw/d) for 104 weeks. The experiment clearly demonstrated forestomach carcinogenicity for PMP. Males were more susceptible than females to induction of forestomach tumours. Dosing was considered adequate based on the decrease in body weight in the treated animals.However, only one dose level was tested.

The LOAEL resulting from these studies were:

LOAEL = 500 mg/kg bw/d for male and female rats, for non carcinogenotoxic effects: decreasing body weights and weight gains, increasing relative liver, kidney weights and hyperplasia in the glandular stomach.

and LOAEL = 500 mg/kg bw/d for male and female rats, for carcinogenotoxic effects: tumour lesions in the forestomach

In This study, tumour lesions were observed only in forestomach of rats. However, such effects are not relevant for humans.

- Hagiwara et al., 1996 (b) and Asakawa et al., 1994, reliability 2:

In the same type of studies (PMP administered to Fisher 344 male rats in diet at dose levels of 0 or 2% PMP (equivalent to 0 and 500 mg/kg bw/d))

, other conclusions were reported: PMP clearly inhibited the development of naturally occurring GST-P+ hepatocytic foci in aged rats, as predicted from the results of medium-term liver bioassays (Ito test).

Moreover, chemopreventive effects of PMP on liver carcinogenesis could not be demonstrated in the previous long-term study (Hagiwara et al., 1996 (a)), since the incidences of spontaneous liver tumours were too low to allow assessment of inhibition.

- Ito et al., 1986 and Hirose et al., 1986, reliability 2:

In these carcinogenicity studies, PMP was administered to male Syrian hamsters (15 animals/ dose) in diet at dose levels of 0 and 1.5% (equivalent to 0 and ca. 225 mg/kg bw/d) for 20 weeks. PMP induced hyperplasia in the forestomach, but no tumorous lesions. The labelling index in the forestomach epithelium and glandular stomach were significantly increased by addition to the diet of PMP. PMP induced epithelial damage and regenerative hyperplasia of the pyloric region. No histopathological lesions were observed in the urinary bladder epithelium. Based on these data, the authors of this study concluded that PMP may act as promotor in two-stage forestomach carcinogenesis.

A LOAEL of 225 mg/kg bw/d has been derived for significant forestomach hyperplasia in male hamsters.

And NOAEL(male hamster) > 225 mg/kg bw/d for tumor incidence (none tumours were noted)

- Hirose et al., 1988, reliability 2:

In this carcinogenicity study, PMP was administered to male F344 rats (15 animals/ dose) in diet at dose levels of 0 or 1.5% (equivalent to 0 and ca. 375 mg/kg bw/d) for 51 weeks. No effects were observed in the mortality or the body weight gain of the treated animals. Liver and kidney weights were significantly higher in animals treated with PMP, when compared to the corresponding control group. PMP induced forestomach hyperplasia in all animals tested. At the dose tested, there was not a treatment related increase in tumor incidence when compared to controls.

LOAEL male rats = 375 mg/kg bw/d for non carcinogenic effects: increase of liver and kidney weight, forestomach hyperplasia.

NOAEL male rats > 375 mg/kg bw/d for tumor incidence (none tumours were noted).

- Hirose et al. 1997, reliability 2:

In this carcinogenicity study, PMP was administered to male F344 rats (30-31 animals/ dose) in diet at dose level of 0 or 0.4% (equivalent to 0 and ca. 100 mg/kg bw/d) for 104 weeks. Final body weights of rats treated with PMP were lower than the control rats. PMP increased significantly the incidence of forestomach papillar or nodular (PN) hyperplasia, as compared with the basal diet. Slightly increased incidences (not significant) of forestomach papillomas were found in the PMP group. At the dose tested, there was not a treatment related increase in tumor incidence when compared to controls.

LOAEL male rats = 100 mg/kg bw/d for non carcinogenic effects: decreased body weight, and increased forestomach findings.

NOAEL male rats = 100 mg/kg bw/d for forestomach tumor incidence (there was not a treatment related increase in tumour incidence).

Dermal route: one study is available for dermal route, from Stenback, 1977 (reliability 2), on mouse or rabbits:

- In a carcinogenicity study, 4-hydroxyanisole was administered to 50 female Swiss mice per dose by cutaneous route at dose levels of 5 and 10 % in methanol or acetone for lifetime (up to 120 weeks). At the doses tested, there were no treatment related effects on clinical signs, body weight or tumor incidence when compared to controls.

Based on this study a dermal NOAEL of 10% in vehicle can be derived for female mice.

- In a carcinogenicity study, 4-hydroxyanisole was administered to 5 New Zealand rabbits per group by cutaneous application in ear at dose levels of 5 or 10 % in acetone or methanol for lifetime, up to 90 weeks. At the doses tested, there were no treatment related effects on survival rate, clinical signs, body weight or tumor incidence when compared to controls.

Based on this study a dermal NOAEL of 10% in vehicle can be derived for rabbits.

All these 7 studies are of reliability 2 as test conditions and results are sufficiently described, even if they didn't totally satisfy the EU or OECD guidelines.

In conclusion, based on oral data, PMP given in diet to rats or hamsters affected only the forestomach, in a manner carcinogenic (papillomas and squamous cell carcinomas) and induced glandular stomach hyperplasia.

Forestomach tumorous lesions observed on rats or hamsters are not relevant for Humans.

Cutaneous application of PMP has no impact on tumour incidence (mice and rabbits).



Several studies were taken into account for assessment and different NOAEL values were identified depending on the study selected.

Justification for selection of carcinogenicity via dermal route endpoint:
Two studies are available, on in mice and the other one in rabbits.

Justification for classification or non-classification

PMP is not considered as carcinogenic based on seven oral data showing only tumour lesions in the forestomach in rats and hamsters and based on one dermal data on which no impact on tumour incidence were observed in mice and rabbits.