Differential expression of facilitative glucose transporter (GLUT) genes in primary lung cancers and their liver metastases.

Glucose uptake is mediated by members of the facilitative glucose transporter (GLUT) family. Malignant cells take up more glucose than their normal counterparts. The aim of this study was to investigate the gene expression levels of the GLUT family, especially GLUT1, GLUT3, and GLUT5 in primary lung cancer, metastatic liver tumors, and normal lung tissues, and to compare the expression levels of primary and metastatic tumors with those of normal tissues. We analyzed 105 autopsy samples (35 primary lung tumors, 35 corresponding normal lung tissues, 25 normal liver tissues, and 10 metastatic liver tumors) from 35 patients using the quantitative reverse transcription polymerase chain reaction. The GLUT1 gene expression levels in primary lung tumors were significantly higher than those in normal lung tissues. In liver metastatic lesions, the GLUT3 and GLUT5 gene expression levels were significantly higher than those in primary lung tumors, but there were no differences in GLUT1 expression levels between primary and metastatic liver tumors. Our results show that the gene expression pattern of the GLUT family is different between primary and metastatic liver tumors and suggest that the energy transporters in metastatic tumors may be different from those in primary tumors.