SOX2 and small cell lung carcinoma: There is a relationship between SOX2 expression and SCLC stage and overall survival. SOX2 expression is associated with more aggressive tumors. An increase in SOX2 activity enhances the proliferation of tumor cells. Overexpression of SOX2 is important for lung CSC function (Saigusa et al., 2009; Wang et al., 2009; Levina et al., 2010; Sholl et al., 2010; Wilbertz et al., 2011; Donnenberg et al., 2012; Perumal et al., 2014; Walcher et al., 2020).