The intensity of a 45 kDa band (red arrow, Fig. 2e) increased proportionally as more Casilio plasmids were added while that of the 50 kDa band remained unchanged (blue arrow, Fig. 2e), suggesting that the 50 kDa band is not the authentic OCT4A protein and may represent a potential new product of POU5F1. Next, we extended the Casilio analyses to several somatic cancer cell lines and further confirmed that the apparent molecular weight of endogenous OCT4A protein in somatic cancer cells was identical to that in PSCs (Supplementary Figure 3B-E). This evidence concerns the gene POU5F1 and cancer.