POU5F1 and cancer: Our results showed an absence of modulation of the expression of the stem cell marker OCT4 in adjacent non-tumor tissue, but did show OCT4 expression in tumor tissue consistent with other authors, who have reported OCT4 protein expression in various human cancer tissues such as stomach [9], pancreas [11], bladder [13], ovary [14], prostate [15], and CRC, but not in normal somatic tissues [38].