Commentary on human mammary preneoplasia. The estrogen receptor-promotion hypothesis

In the carcinogenic process, promotion is the process whereby an initiated tissue develops focal proliferations which act as proximate precursors. The evidence obtained from the immunocytochemical staining by monoclonal anti-receptor antibodies indicates that the early steps (atypical hyperplasias) in the carcinogenic process of the breast show an increased and homogeneous expression of the estrogen receptor. These observations suggest that the persistent sensitivity to estrogen may be critical in sustaining the growth of mammary preneoplastic changes and their progression to ultimate precursors and to invasive cancer.