IL17A and neoplasm: The activation of IL-17R at the surface of synovial sarcoma cells by IL-17A [64] was found to recruit ERK1/2, p38 MAPK and c-Jun N-terminal kinases (JNKs), and then to activate AP-1, finally leading to an increase of MMP-3 mRNA and protein expression, which has been shown to stimulate tumor development in breast and lung [93,94].