Background: Many literature reviews report vitamin E supplementation as a benefit chemopreventive and adjuvant therapy in breast and prostate cancers. We investigated in the present work, alpha-tocopherol (α-T) expression (the current active form of vitamin E) from tissues of Congolese patients neither smokers nor alcohol drinkers and without intake antioxidant vitamins supplement. Methods: α-T was analysed in one normal placenta of nine weeks of gestation and in nineteen cancerous tissues, including seven breast cancers, six prostate cancers, and six gestational choriocarcinomas. The study was performed by immunohistochemistry method after diagnosis confirmation by histological analysis. Results: α-T staining in membrane cells and collagen fibers presented a moderate expression in healthy sections of tissues (positive control), but the labelling was strong in breast, prostate adenocarcinomas, and in choriocarcinomas. Conclusion: Tumors immunohistochemistry of α-tocopherol in breast, prostate cancers and in choriocarcinoma show elevated immunostaining suggesting a probable oncogenic effect of the micronutrient.