USP53 and breast carcinoma: We detected USP53 mRNA expression levels in human immortalized mammary epithelial cell line MCF-12 A and six breast cancer cell lines (MCF-7, T47D, BT474, SKBR3, MDA-MB-453 and MDA-MB-231), and found that the expression of USP53 in all breast cancer cell lines, except TD47, was significantly lower than that in MCF-12 A cell line (Fig. 3A).