To determine whether HCP5-132aa was expressed endogenously, we conducted western blot analysis to detect HCP5-132aa protein expression in normal human mammary epithelial cells MCF-10A and breast cancer cell lines T47D, MCF-7, SKBR3, MDA-MB-231, MDA-MB-468, and HCC-1937 cells. The gene discussed is HCP5; the disease is breast cancer.