PGR and breast cancer: TRPS1 was previously identified to be overexpressed in breast cancer,[38] and higher TRPS1 expression is significantly associated with estrogen receptor (ER)-α, progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression, as well as improved survival in breast cancer patients.[37] Consistently, we found that TRPS1 expression was significantly elevated in luminal breast cancer cells as compared with basal breast cancer cells using the expression data of 51 breast cancer cell lines[50] (Figure 4A).