Facilitative glucose transporter expression in human cancer tissue

Glucose utilisation by cancer cells is greatly enhanced when compared with that by normal tissue. Glucose is taken up by cells and then phosphorylated to glucose-6-phosphate. Facilitative hexose uptake is achieved by five tra nsmembrane transporters, termed glut 1-5, which are protein products of the ir respective GLUT genes: Glut types differ in their kinetics, which are ta ilored to the requirements of the cell type they serve, although more than one glut may be expressed by a particular cell type. Herein are reviewed th e results from approximately 30 studies which examined glut expression in h uman cancer tissue. These studies measured GLUT messenger RNA (mRNA) either using the reverse-transcriptase polymerase chain reaction or by Northern b lot analysis, or detected glut proteins using the appropriate antibodies. T umour tissue is frequently associated with the abnormal and/or over-express ion of gluts, especially glut1. Some tumour cells express specific GL UT mR NA but not the respective protein. Some studies have reported associations between glut expression and proliferative indices, whilst others suggest th at glut may be of prognostic significance, especially in lung cancer.