IL17A and colorectal cancer: Zhang et al. showed significant increase of mRNA expression of IL-17 and IL-23 in serum and also tumor tissues of patients with advanced gastric cancer.32 A significantly higher serum level of IL-23 in patients with colorectal cancer is strongly associated with overexpression of VEGF.33 However, Shime et al. reported increased expression of IL-23 mRNA in tumor microenvironment of patients with lung adenocarcinoma.