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Administrative data

Description of key information

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed

Additional information

Squalene was painted in undiluted form six times weekly for a total of 25 times on the backs of 16 C57B1 mice (the total dose was 1.3 g per mouse). Eight mice survived 100 days, but five of them developed “lymphocytic type of tumors” between days 272 and 849. Tumors were primarily found in the thymus and mesentary of the thymus. Metastases and/or lymphocytic invasions were detected in the peripheral lymph glands, lungs, spleen, liver, and kidneys.[1] This study needs confirmation.

A 20% solution of Squalene in decahydronaphthalene (Decalin) was applied as a tumor promoter twice weekly to the skin of male C3H mice which had been initiated once with 240 ug of 7,12-dimethylbenz(a)anthracene (DMBA). After 30 weeks of application, two out of 12 mice developed malignant skin tumors. In the control group, where 100 percent decahydronaphthalene was used as a promoter, two out of 15 mice developed benign skin tumours [2].

In a skin painting study, both freshly purified and “aged” Squalene (compound that had been exposed to open air at 37 “C for four weeks) were painted three times weekly for 14 weeks in undiluted form on the backs of C57B1 and C57BR mice. No skin tumors developed. When a similar procedure was used to paint fresh and “aged” Squalene in combination with 0.3% 3-methylcholanthrene (3-MCA), each form of the compound was determined to be inactive as a cocarcinogen. When 0.3% 3-MCA in Squalene was “aged” by being left to stand for four weeks in the open air at 37 OC, 3-MCA lost its carcinogenic effect on mouse skin. According to the authors, these observations suggest that Squalene in human sebum may play a protective role against hydrocarbon carcinogens.[3][4]

[1] KRONINC, F. (1959). The induction of leukemia in C,,B1 mice after painting the dorsal skin with shortchain fatty acids, fatty acid esters, and with squalene. Acta Unio. Intern. contra Cancrum 15, 619-26.

[2] HORTON, A.W., ESHLEMAN, D.N., SCHUFF, A.R., and PERMAN, W.H. (1976). Correlation of cocarcinogenic activity among n-alkalines with their physical effects on phospholipid micelles. J. Nat. Can. Inst. 56(2), 387-91.

[3] SOBEL, H. and MARMORSTON, J. (1956). The possible role of squalene as a protective agent in sebum. Cancer Res. 16, 500-3.

[4] SOBEL, H., MARMORSTON, I., WRIGHT, E.G., and GARCIA, E. (1957). Determination of squalene in sebum from the forehead of patients with skin cancer. J. Invest. Dermatol. 29, 269-71.

Justification for classification or non-classification