PTGS2 and skin neoplasm: The additional study stated the anti-proliferation effect of 6-gingerol on human skin keratinocyte cell lines as a consequence of MAPK and AP-1 signaling pathways (49) and on mouse skin tumor cells through the activation of NF-kappa B(NF-κB), p38 MAPK, and cyclooxygenase-2 (COX-2) expression as reported in a published study (50).