SOX2 and cancer: In the current study, we could induce CSC properties in colon cancer cells by using an artificial system involving the forced expression of OCT3/4, SOX2 and KLF4. Although these factors were individually reported to be correlated with the malignant behavior and poor prognosis in various cancers [37]–[42], it is unclear whether there are any cells that spontaneously overexpress OCT3/4, SOX2 and KLF4 in colon cancer tissues.