PPM1F and breast cancer: To investigate the protein expression profiles of PPM1F and α9-nAChR in human breast cancer cell lines, we performed Western blotting on 10 breast cancer cell lines (BT474, AU565, SKBR3, ZR75, BT483, T47D, MDA-MB-231, MCF-7, MDA-MB-453 and HS578T) and two normal breast epithelial cell lines (HBL100, MCF-10A) (Figure 2A).