CXCL8 and renal cell carcinoma: Blood baseline levels of VEGF, soluble (s)VEGFR2, (s)VEGFR3, IL-6 and single-nucleotide polymorphysms (SNPs) of VEGF/VEGFR and IL-8 genes, among others, have been associated with response and outcome in RCC patients treated with sunitinib and/or pazopanib [9].