HK2 and nonpapillary renal cell carcinoma: When glucose enters ccRCC cells, it is phosphorylated to glucose-6-phosphate (G6P) by HK-2, and part of it is converted to fructose-6-phosphate (F6P) by isomerase to participate in the hexosamine biosynthesis pathway, in which glucose-6-phosphate dehydrogenase (G6PD) is modified by O-GlCNAC (OGT).