CXCR1 and melanoma: Several studies found that upregulation of CXCR1 or CXCR2 resulted in an increase of melanoma cell proliferation and invasion, while knockdown of CXCR1 and/or CXCR2 led to inhibition of melanoma cell growth, motility, and vascularization both in vitro and in vivo [60,61].