ERT courses are currently administered to the elderly, and especially to aged menopausal women. However, as already discussed above, the long-term exposure to synthetic estrogenis a risk factor for the development of breast cancer [80], and endometrial cancer [81,82]. Thus, despite the many reported potential benefits of treatment with P. mirifica tuber extracts,it remains important to clarify if P. mirifica also induces thedevelopment of breast and endometrial cancers. Consistentwith its antioxidative and antiproliferative effects, pretreatment of a high dose (1000 mg/(kg$d)) of P. mirifica to female rats for four weeks before the induction of a breast tumor by a single injection of the 7,12-DMBA carcinogen actually resulted in decreased levels of tumor development and multiplicity.The proposed mechanism of action was through the suppression of ER expression, especially for ERα [102].