NOTCH1 and prostate cancer: Decreased levels of Notch1 protein and mRNA expression were also found in several widely used prostate cancer cell lines (RWPE2, LNCaP, 22rv1, PC3 and DU145) relatively to primary prostate epithelial cells (PrEC or hPEC) or to an immortalized but non-tumorigenic prostate cell line (RWPE1) [38] (Figure 1C–1D).