1. Introduction
breast cancer
MAMMARY TUMOR, PROLIFERATIVE, BREAST CANCER
Recent studies suggest estradiol (EMenopausal hormone treatment (MHT) is used for the alleviation of climacteric symptoms but has been associated with an increased risk of breast cancer after long-term treatment [Sex hormones in different combinations, doses, regimens, and durations may have various effects on the breast. Our group and others have shown that CEE in combination with the synthetic progestogen MPA induces a different genetic and proliferative response in breast cells in vivo and in vitro than when given together with natural micronized progesterone [The purpose of this study was to evaluate any differences in the change in expression of several genes relevant to mammary tumor development in the treatment groups.