Evidence accumulating in the last few years has led to wide acceptance of the theory that new growths of mammary tissue are due to abnormal endocrine stimulation. Examination of this evidence shows, however, that it pertains largely to mammary tumors in animals and that the precise nature of the hypothetic glandular dysfunction, even with the much studied mouse cancer, is not known. Especially has little consideration been given the extent to which generalizations derived from animal study may justifiably be applied to the explanation of tumors occurring in man.
Nevertheless, mammary cancer in the mouse continues to afford the best starting point for the study of conditions under which cancer of the breast may develop. Past experiments have already shown the general importance of the ovarian hormone, since it has been demonstrated that the incidence of tumors can be lowered by oophorectomy and raised by administration of estrogenic substances. The
TAYLOR HC, WALTMAN CA. HYPERPLASIAS OF THE MAMMARY GLAND IN THE HUMAN BEING AND IN THE MOUSEMORPHOLOGIC AND ETIOLOGIC CONTRASTS. Arch Surg. 1940;40(4):733-820. doi:10.1001/archsurg.1940.04080030151011