XIAP and renal cell carcinoma: Several potentially relevant biomarkers for RCC are reported in the literature, such as Von Hippel-Lindau (VHL), survivin, XIAP (X-linked inhibitor of apoptosis), MCL-1 (myeloid cell leukemia-1), HIF1α (hypoxia-inducible factor 1α), HIF2α, NRF2 (nuclear factor erythroid 2-Related Factor 2), transglutaminase 2 (TGase 2), MDM2 (mouse double minute 2), TP53/p53, KRAS, and AKT [10], but for many of them, there are conflicting data on whether they play a role as oncogenes or tumor suppressors and whether they may be considered effective biomarkers.