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See in this report: Vit. E-su. & tumors at section 4.3.1 Results: Vitamin E-acetate effect.  - And Section "5.1. E-Ac promotion of HCCs and induction of hepatomegaly:"

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Tocopheryl acetate, also known as vitamin E acetate, [is the common vitamin E supplement purchased in stores,] with the molecular formula C31H52O3. It is the ester of acetic acid and tocopherol (true vitamin E). It is often used in dermatological products such as skin creams. Tocopheryl acetate is not oxidized and can penetrate through the skin to the living cells, where about 5% is converted to free tocopherol and provides beneficial antioxidant effects.[1]
Tocopheryl acetate is used as an alternative to tocopherol itself because the phenolic hydroxyl group is blocked, providing a less acidic product with a longer shelf life. It is believed that the acetate is slowly hydrolyzed once it is absorbed into the skin, regenerating tocopherol and providing protection against the sun's ultraviolet rays.[2]
References
1. Linus Pauling Institute Research Report: All About E
2. Beijersbergen van Henegouwen G, Junginger H, de Vries H (1995). "Hydrolysis of RRR-alpha-tocopheryl acetate (vitamin E acetate) in the skin and its UV protecting activity (an in vivo study with the rat)". J Photochem Photobiol B. 29 (1): 45–51. doi:10.1016/1011-1344(95)90251-1. PMID 7472802.
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Virchows Arch A Pathol Anat Histopathol. 1985;405(3):285-97.
Initiation of a transplantable fibrosarcoma by the synergism of two non-initiators, alpha-tocopherol and soya oil. P. Constantinides and M. Harkey

Abstract
When, in the course of an ageing study, alpha-tocopherol (vitamin E), dissolved in soya oil, was given to 22 Balb/c mice once a week subcutaneously for 10 months, it caused the development of vigorously growing fibrosarcomata at the site of the injections in 17 (77.3%) of the animals. The tumors produced in this manner proved eminently transplantable into syngeneic Balb/c hosts, and have been serially transplanted every 3-4 weeks for over 3 years in such recipients, having reached their 44th transplantation cycle at the present time; upon transplantation, they now exhibit a 100% "take" incidence and proliferate extremely rapidly, growing from pin-head size to up to half the weight of a whole recipient mouse within 3 weeks. All fibrosarcomata showed marked mitotic activity, invasion of adjacent tissues and extensive necrotic areas, and they became more undifferentiated after the third transplantation cycle. Neither pure alpha-tocopherol alone nor soya oil alone produced any tumors when given subcutaneously once a week, for 10 months to groups of 22 Balb/c mice each. It is concluded that the two agents alpha-tocopherol and soya oil which proved non-carcinogenic when injected alone, developed a powerful carcinogenic effect when they acted on subcutaneous connective tissue simultaneously. The possible mechanisms of this phenomenon are discussed.
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Jpn J Cancer Res. 1991 May;82(5):511-7.
Induction of transplantable tumors by repeated subcutaneous injections of natural and synthetic vitamin E in mice and rats. Nitta Y1, Kamiya K, Tanimoto M, Sadamoto S, Niwa O, Yokoro K.

Abstract
Natural vitamin E and synthetic vitamin E (dl-alpha-tocopheryl acetate) were tested for their tumorigenicity in rodents. Transplantable tumors, at the site of injection, were induced by repeated injections of these compounds in two strains of mice, NFS/N and C57BL/6N x C3H/He F1, and in a strain of rats, Fischer 344. Natural vitamin E ( free tocopherol) was tumorigenic in both strains of female mice only when injected with soya oil. In contrast, dl-alpha-tocopheryl acetate alone was capable of inducing tumors in Fischer 344 rats. Only one out of 5 male NFS/N mice given dl-alpha-tocopheryl acetate developed a tumor. Therefore, Fischer 344 rats were more susceptible to tumor formation by dl-alpha-tocopheryl acetate than NFS/N mice. dl-alpha-Tocopheryl acetate with soya oil or with palm oil also resulted in the formation of transplantable tumors in NFS/N mice and Fischer 344 rats. There was no difference in the tumor incidence between mice treated with dl-alpha-tocopheryl acetate alone and dl-alpha-tocopheryl acetate plus soya oil or palm oil. However, in rats, the incidence was lower for a group treated with dl-alpha-tocopheryl acetate plus palm oil than for those with dl-alpha-tocopheryl acetate alone and with dl-alpha-tocopheryl acetate plus soya oil.
PMID: 1905698