PCNA and cancer: The aim of this study was therefore to simultaneously investigate the influences imparted by Wharton's Jelly-derived MSCs (WJ-MSCs) and the fd-ECM on genes that are highly expressed in WHCO1 and MDA-MB 231 cancer cells and these include PCNA, Bcl-2, Bcl-xL, p53, p21, proteases, and their inhibitors [10, 26, 27, 29, 30].