IL17A and neoplasm: However, the presence of IL-17 induces the conversion of healthy stem cells to CSCs, thus promoting tumorigenesis.294,304 Subsequently, IL-17 promotes the growth and reproduction of CSCs by acting on the tumor or its microenvironment, accelerating tumor progression.305–308 Moreover, IL-17 can act on quiescent CSCs to cause EMT-like changes and transform them into invasive CSCs, promoting tumor invasion and metastasis.294 Thus, IL-17 has an important role in tumor progression.