KLF4 and neoplasm: Using the Spearman rank-order correlation (2-tailed), strong positive correlation between NANOG and all the tested regulators was observed in tumor samples as follows: OCT4 (rs = 0.395, p = 0.001), KLF4 (rs = 0.570, p = 0.001), NOTCH1 (rs = 0.515, p = 0.001), SOX2 (rs = 0.292, p = 0.008), and AGR2 (rs = 0.219, p = 0.048).