Immune analysis of expression of IL-17 relative ligands and their receptors in bladder cancer: comparison with polyp and cystitis

Background: Bladder cancer, cystitis and bladder polyp are the most common urinary system diseases all over the world. Our former research results show that IL-17A and IL-17 F contribute to the pathogenesis of benign prostatic hyperplasia (BPH) and prostate cancer (Pca) while IL-17E interacting with IL-17RB might have an anti-tumor effect. Results: Using imunohistochemistry, we systemically compared immunoreactivity of ligands (IL-17A, E and F) and receptors (IL-17RA, IL-17RB and IL-17RC) of IL-17 family, infiltration of inflammatory cells and changes of structural cells (fibroblast cells, smooth muscle and vascular endothelial cells) in sections of bladder tissues from subjects with bladder cancer, cystitis and bladder polyp. Compared with subjects with cystitis, immunoreactivity for IL-17A, IL-17 F and IL-17RC was significantly elevated in the group of bladder cancer (p < 0.01), while immunoreactivity of IL-17E, IL-17RA and IL-17RB, and the infiltrating neutrophils were decreased (p < 0.05). The numbers of infiltrating lymphocytes and phagocytes and CD31(+) blood vessels and immunoreactivity of CD90(+) fibroblasts were also elevated in patients with bladder cancer compared with those of cystitis. The patterns of IL-17 ligands and receptors, and inflammatory cells and structural cells varied in cystitis, bladder polyp and bladder cancer. In bladder cancer, immunoreactivity of IL-17E and IL-17 F was positively correlated with smooth muscles and lymphocytes, respectively. In addition, immunoreactivity of IL-17A and IL-17E was positively correlated with their receptors IL-17RA and IL-17RB respectively. Conclusions: The data suggest that changed patterns of expression of the IL-17 cytokine family ligands and receptors might be associated with infiltration of inflammatory cells and structural cells (CD90(+) fibroblasts and CD31(+) blood vessels), which might also contribute to occurrence and development in bladder cancer.