All these suggest that the expression of PCP4/PEP19 is not connected to the induction of aromatase expression in MCF-7 cells, although the PCP4/PEP19 promotes cancer cell proliferation and survival mediated through its anti-apoptotic effects and also increases cancer cell migration and invasion in both MCF-7 and SK-BR-3 cells [13, 16]. This evidence concerns the gene PCP4 and cancer.