GPI and nonpapillary renal cell carcinoma: Analysis of the glycolytic enzymes glucose-6-phosphate isomerase (G6PI), L-lactate dehydrogenase A chain (LDH-A) and pyruvate kinase isoform M2 (PKM2) demonstrated an increased expression of these proteins in MUC1H ccRCC as compared with MUC1L tumors and non-neoplastic tissue.