HK2 and rheumatoid arthritis: The expression of HK2, fructose-6-phosphate 2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), and pyruvate kinase 2 (PKM2), all metabolism-related enzymes of the glycolytic pathway, were significantly increased in RA-FLS, suggesting increased aerobic glycolysis in RA-FLS (80, 81).