In polyoma middle T- (PyMT-) induced breast cancer models, IL-17 induced the secretion of CXCL1 and CXCL5 from mammary carcinoma cells and increased the suppressive function of myeloid derived suppressor cells (MDSCs) on T cells by upregulating arginase (Arg), indoleamine 2,3-dioxygenase (IDO), and prostaglandin- endoperoxide synthase- (COX-) 2 expression [35]. The gene discussed is IL17A; the disease is breast cancer.