HIF1A and nonpapillary renal cell carcinoma: Additionally, in ccRCC, HIF-1α upregulates the expression of glycolytic enzymes, such as hexokinase (HK), neuron-specific enolase (NSE), phosphoglycerate kinase (PGK), and pyruvate kinase (PK), further corroborating the Warburg effect (38, 39).