The functional mechanism of the SOX2 gene for breast cancer suggests that the gene’s contribution to tumorigenicity is facilitated by passing the cell from step G1 to S. Although the KLF4 gene was initially recognized as anti-epitope and anti-apoptosis in differentiated cells, recent studies have shown that the expression of this gene increases in many cancers such as gastric, intestinal, bladder, and kidney cancer, and it is closely associated with poor prognosis (El-Karim et al., 2013; Feizi et al., 2013; Schoenhals et al., 2013). This evidence concerns the gene SOX2 and cancer.