Our previous study revealed that activating p38 mitogen-activated protein kinase, a member of the MAPK family, was capable of enhancing Arg2 expression in human endothelial cells[48]; therefore, sorafenib-induced Arg2 suppression might occur through the inhibitory effects of sorafenib on the MAPK/ERK pathway in melanoma cells[49]. Here, ARG2 is linked to melanoma.