JUN and nasopharyngeal carcinoma: Furthermore, in another human NPC experiment, IL-17A was found to upregulate COX2 levels and promote PGE2 secretion by activating the Ap1/c-Fos and JNK/c-Jun signaling pathways; the MAPK pathway includes P38, JNK, and ERK, and AP-1 is a downstream protein of the MAPK pathway (82).