CXCR4 and renal cell carcinoma: In human renal cell carcinoma (RCC), the most common type of kidney cancer in humans [167], blood derived monocytes display a distinct transcriptional profile characterized by the upregulation of pro-inflammatory cytokines and chemokines, pro-tumor genes, (e.g., COX2, IL-8, VEGFA, MMP19, MMP10, CXCR4, and HIF1A) and polarization-related genes [168].