PFKFB3 and neoplasm: Among other things the following: i) tumor ECs upregulate the glucose transporter GLUT-1 (64), ii) tumor ECs directly or indirectly upregulate the expression of rate limiting glycolytic enzymes, e.g. Phosphofructokinase-2/fructose-2,6-bisphosphatase (PFKFB), specifically its isoenzyme PFKFB3 (65) and iii) ECs express high amounts of lactate transporters (e.g. MCT1) (66).