Furthermore, IL-17 induces formation of a multi-protein signaling complex that comprises IL-17R-ACT1-TRAF4- mitogen-activated protein kinase kinase kinase (MEKK)3-MEK5, which activates extracellular signal-regulated kinase (ERK)5, but not NF-κB, p38, JNK, or ERK1/2, inducing expression of IL-17 target genes, which leads to keratinocyte proliferation and eventually tumor formation [81]. Here, IL17A is linked to neoplasm.