Overexpression of Glut-1 glucose transporter in human breast cancer. An immunohistochemical study.
BACKGROUND
Breast cancers have higher than normal glucose metabolism, but the mechanism of glucose entry into these tumors is not well understood.


METHODS
The expression of five facilitative glucose transporters, Glut-1 (erythrocyte type), Glut-2 (liver type), Glut-3 (brain type), Glut-4 (muscle/fat type), and Glut-5 (small intestine type), was studied by immunohistochemistry of paraffin sections from 12 primary human breast cancers and 8 lymph node metastases from 2 patients. Rat tissues known to express these glucose transporters were used as controls.


RESULTS
All the primary breast cancers and the lymph node metastases were positive for Glut-1. This transporter was expressed on the cell membrane and in the cytoplasm of the tumor cells, but exhibited marked intratumoral and intertumoral variability in the proportions of positive cells and the intensity of staining. Staining of the normal mammary epithelium, if present, was much lower than observed in tumor cells from the same patient. Glut-2 was expressed in all of the tumors, but the intensity of staining was not consistently stronger than that seen in healthy breast. Clusters of Glut-4-positive granule were observed in cells in six of the tumors. None of the tumors or the healthy breast in the tissues studied expressed Glut-3 or Glut-5.


CONCLUSIONS
Higher expression of the glucose transporter Glut-1 by breast cancer cells compared with the healthy breast tissue is common. Increased glucose transporter protein expression may contribute to the increased uptake of 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) by these tumors observed by positron emission tomography (PET) imaging.
Brown
R S
RS
Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0028.
Wahl
R L
RL
D001692:Biological Transport; D014408:Biomarkers, Tumor / Q000378:metabolism; D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005947:Glucose / Q000378:metabolism*; D051272:Glucose Transporter Type 1; D051273:Glucose Transporter Type 2; D051274:Glucose Transporter Type 3; D051275:Glucose Transporter Type 4; D051296:Glucose Transporter Type 5; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology; D008207:Lymphatic Metastasis; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009124:Muscle Proteins; D009419:Nerve Tissue Proteins
D014408:Biomarkers, Tumor; D051272:Glucose Transporter Type 1; D051273:Glucose Transporter Type 2; D051274:Glucose Transporter Type 3; D051275:Glucose Transporter Type 4; D051296:Glucose Transporter Type 5; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D009419:Nerve Tissue Proteins; C495677:SLC2A1 protein, human; C495687:SLC2A3 protein, human; C495692:SLC2A4 protein, human; D005947:Glucose