IL17A and neoplasm: In studies utilizing various genetically modified murine tumor models, investigators have shown that endogenous IL-17 (such as IL-17 derived from Th17 cells infiltrating sites of tumor growth) could promote tumor growth by inducing tumor vascularization, suggesting that the cellular targets of IL-17 in the tumor microenvironment can be vascular endothelial cells, stromal cells, and cells of the tumor itself (Numasaki et al., 2003; Wilke et al., 2011).