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. This evidence concerns the gene IL17A and cystitis.