PCNA and cancer: Low-dose DBP exposure revealed enhanced proliferation and expression of cell cycle genes (including cyclin-D, CCND1, Proliferating Cell Nuclear Antigen, PCNA, and cyclin-dependent kinase 4, CDK4) on prostate (PC3 and 22RV1) (10−6–10−7 M DBP) [35] and breast (BG1) cancer cell lines (10−5–10−8 M DBP) [36].