POU5F1 and breast cancer: OCT4A is not expressed in breast cancer cells, such as MDA‐MB‐231 and MCF‐7 cells.39OCT4B is amplified and promotes an aggressive phenotype in gastric cancer.40 Moreover, the OCT4 pseudogenes OCT4‐pg1 and OCT4‐pg5 were found in somatic cancers.2OCT4‐pg4 is positively correlated with OCT4 in hepatocellular carcinoma, OCT4‐induction may promote OCT4‐pg4 expression in BCCs.41 Remarkably, OCT4 pseudogenes did not show OCT4A activities.