Expression of Estrogen Receptors a andin Early Steps of Human Breast Carcinogenesis

摘要

Association of hormonal factors and preinvasive mammary lesions increase the risk of sporadic breast cancer (BC) incidence. Indeed, the mitogenic activity of estrogens and their role as a promoter of BC was confirmed by epidemiological, clinical, and experimental studies (1). Preinvasive mammary lesions frequently precede the development of invasive BC. They correspond to nonproliferative and proliferative benign breast disease without or with atypia and ductal carcinoma in-situ (DCIS) (2).Because of the difficult access to benign mammary lesions with high risk, the biological pattern of the final steps in BC are more studied than the initial steps, both in vivo invasive BCs and in vitro cancer cell lines.The multistep model of carcinogenesis established for colorectal cancer (3) might be useful in understanding mammary carcinogenesis starting from normal epithelial cells and ending as an invasive BC through high risk proliferative lesions and DCIS (4, 5).