HK2 and nonpapillary renal cell carcinoma: Prior studies have shown that in ccRCC, HIF1α upregulates expression of genes that mediate glucose uptake, SLC2A1 and SLC2A3, along with several glycolytic enzymes, including HK2, PFK-1, and LDHA, in accord with an oncogenic switch to aerobic glycolysis [3,21].