OBJECTIVETo investigate the association between galectin-3 expression and biological behaviors of human colorectal carcinoma.

METHODSSP immunohistochemistry was used to detect the expression of galectin-3 in 158 cases of paraffin-embedded specimens (including 30 normal mucosa, 25 adenoma, 65 carcinoma and 38 metastatic tumor specimens). Real-time RT-PCR was performed to detect galectin-3 mRNA expression in 31 pairs of fresh carcinoma and corresponding adjacent normal mucosa specimens.

RESULTSThe expression levels of galectin-3 was significantly different between normal mucosa and adenoma tissues (P<0.001), and moderately or well differentiated colorectal carcinomas showed significantly lower expression of the galectin-3 than the poorly differentiated carcinomas (P=0.03). Invasive carcinomas exhibited higher galectin-3 expression levels than non-invasive ones (P<0.001), and galectin-3 expression in the colorectal carcinomas was significantly related with the lymph node metastasis (P<0.001). Galectin-3 mRNA expression in poorly differentiated colorectal carcinomas was about 1.98 times that in moderately or well differentiated colorectal carcinomas (P=0.03), and in invasive carcinomas, galectin-3 mRNA expression was 1.67 times higher than that in non-invasive ones (P<0.001). Galectin-3 mRNA expression in tumors with lymph node metastasis was 1.91 times that in non-metastatic tumors (P=0.013).

CONCLUSIONGalectin-3 expression is positively correlated with and invasion, poor differentiation and metastasis of colorectal carcinoma.