Transforming Growth Factor- β Type II Receptor Is Infrequently Expressed in Human Breast Cancer

Abstract: TGFβ has been shown to suppress tumor growth in vitro through interaction with TGFβ type II receptor (TGFβ-RII). Although a significant percentage of breast carcinomas have been shown to express TGFβ, TGFβ expression was not found to influence survival of patients with breast cancer. In order to determine whether the lack of influence of TGFβ expression on the biologic behavior of breast cancer is due to lack of or infrequent expression of TGFβ-RII, we studied the expression of TGFβ-RII in 11 1 cases of invasive breast carcinoma by immunohistochemistry. The percent of breast cancer cells which stained for TGFβ-RII was subjectively scored as 0 (negative), >10%, 10–25%. 25–50%, and >50%. Of the invasive breast carcinomas, 81 (73%) were completely negative, 22 (20%) had 40% of the cells positive, and only 3 (3%) had >50% of the cells positive for TGFβ-RII. In benign breast tissue in the same tissue sections, myoepithelial cells were always positive for TGFβ-RII, whereas stromal cells were negative, and benign epithelial cells were rarely positive. We conclude that TGFβ-RII is consistently expressed in myoepithelial cells of the human breast, and rarely in epithelial cells, and that the infrequent expression of TGFβ-RII by invasive breast carcinomas, may explain why TGFβ expression does not appear to influence the outcome of patients with breast cancer.