SOX2 and cancer: Despite its active involvements in self-renewal and maintenance of stemness of embryonic- and neuronal stem cells (SCs), reprogramming somatic cells into induced pluripotent stem cells (iPSCs), and in regenerative medicine (Takahashi and Yamanaka, 2006; Niwa, 2007; Silva and Smith, 2008; Young, 2011); recent studies have demonstrated the oncogenic roles of SOX2 in cancers (Weina and Utikal, 2014; Wuebben and Rizzino, 2017).