IL6 and melanoma: In malignant melanoma, squamous cell carcinoma (SCC), hepatocellular carcinoma (HCC), ovarian and bladder cancers, the expression levels of IL-6 were found to be positively correlated with the number of MDSC (Meyer et al., 2011; Chen et al., 2014; Bjoern et al., 2016; Lin et al., 2017; Wu et al., 2017; Xu et al., 2017; Yang et al., 2017; Tsai et al., 2019).