NANOG and ovarian cancer: At the same time, the expression level of ALKBH5 was significantly increased in SKOV‐3 and Ishikawa co‐cultured cells (Figure 5B); meanwhile, all the expression levels of NANOG, SOX‐2 and OCT‐4 increased in ovarian cancer tissues (Figure 5C), but fell in ovarian cancer cell lines (Figure 5D).