Through a variety of mechanisms, including the direct recruitment of MDSC, the synthesis of GM-CSF in oncogene-driven cancer cells, the stimulation of the epithelial-mesenchymal transition, and the production of VEFG and chemokines (such as CXCL12 and CXCR4), IL-17 exerts a pro-tumorigenic effect. The gene discussed is CXCR4; the disease is cancer.