Lack of correlation between the presence of estrogen receptor and histological type of mammary cancer induced by 7,12-dimethylbenz[alpha]anthracene.

The relation between the histological type and the presence of estrogen receptor or response to oophorectomy was investigated in the mammary cancer induced by 7,12-dimethylbenz[alpha]anthracene in Spargue-Dawley rats. The estrogen receptor was present in 75.0% (3/4) of poorly differentiated cancer and in 62.5% (10/16) of well-differentiated cancer. The histological degree of differentiation or grading of the rat mammary cancer did not affect the presence of the estrogen receptor or response to oophorectomy. In contrast, there was clearly a good correlation between the presence of the receptor and response to oophorectomy.