Glut1 expression in T1 and T2 stage colorectal carcinomas: its relationship to clinicopathological features

Glucose uptake is mediated by glucose transporter (Glut) proteins, which ex hibit altered expression in a variety of malignant neoplasms. Glut1 express ion is thought to be a potential marker for malignant transformation. The a im of the present study was to investigate the expression of Glut1 protein in colorectal adenomas, T1 and T2 stage carcinomas. Immunohistochemical det ection of Glut1 protein was examined in 141 formalin-fixed and paraffin-emb edded colorectal tumour specimens (57 adenomas, 84 carcinomas). The degree of Glut1 immunostaining of a specimen was graded according to the proportio n of Glut1-positive cells in it; absent (positive cells are 0%), weakly pos itive (less than 10%), moderately positive (10-50%), and strongly positive (more than 50%). Glut1 expression was present in 18% of the adenomas with l ow-grade dysplasia, and in 63% of the adenomas with high-grade dysplasia. T he positivity in such lesions was usually weak, but was moderate in 18% of the adenomas with high grade dysplasia. For the carcinomas, there were sign ificant correlations between Glut1-positivity and depth of invasion (T1 45% versus T2 74%, P < 0.01), histological differentiation (well 49% versus mo derately to poorly 74%, P < 0.05) and morphological type (polypoid 42% vers us depressed 73%, P < 0.05), if the cut-off value was set at 10% of cells. In conclusion, we clarified the relationship between Glut1 expression and c linicopathological features in T1 and T2 stage colorectal carcinomas, and o ur results suggested a high malignant potential of the depressed-type carci noma. (C) 2001 Elsevier Science Ltd. All rights reserved.