BCL2 and colorectal cancer: Levels of protein expression were comparable to colorectal cancer cell lines HT29, HCT116, SW620 and LS174T, which are known to rely on high BCL2 family member expression to maintain viability.26 We also checked CDK4 expression in ES cell lines as a proliferation marker, which was upregulated compared with control cells (human prostate epithelial RWPE-1 cells; Figure 5a).