To validate the expression of TNFR2 in breast cancer cells, we first detected its mRNA and protein levels in normal human mammary epithelial cell line MCF-10A and a number of human breast cancer cell lines (MCF7, BT549, BT474, and MDA-MB-453), as well as in murine breast cancer cell line 4T1 and murine mammary epithelial cell HC11. The gene discussed is TNFRSF1B; the disease is breast cancer.