PPA1 and breast cancer: A western blot analysis was conducted for the expression of PPA1 in four lung cancer cell lines (A549, H1299, H460, SK‐MES‐1), four ovarian cancer cell lines (SKOV3, OVCAR3, ES2, A2780), four hepatoma cell lines (SK‐hep1, HepG2, Hep3B, SMMC‐7721), four breast cancer cell lines (MCF‐7, MDA‐MB‐468, T47D, MDA‐MB‐231), and their corresponding noncancerous cell lines (MRC5, IOSE80, L02, MCF‐10A).