IL6 and cancer: CSCs can not only transform into cancer cells and enhance their resistance to chemoradiotherapy, but also secrete immunosuppressive cytokines such as transforming growth factor-β (TGF-β), interleukin-6 (IL-6), IL-10, and IL-13, which can induce immune evasion of tumor cells (Schatton and Frank, 2009; Zhang et al., 2019; Jahanafrooz et al., 2020).