OBJECTIVETo investigate the expression of phosphatase of regenerating liver-3 (PRL- 3) mRNA and evaluate its relationship with tumor invasion and metastasis in human colorectal carcinoma.

METHODSThe expression level of PRL-3 mRNA was examined semi-quantitatively in surgically resected tumor specimens, paired paratumor normal tissues from 46 CRC patients, metastatic lymph nodes and liver metastases from 18 cases with metastasis,adenoma tissues from 6 patients with colorectal adenoma (CRA). In addition,the mutation of PRL-3 gene was examined by PCR-SSCP.

RESULTSThe PRL-3 mRNA level was increased in primary CRC tissues as compared with paired paratumor normal tissues (1.6+/- 0.7 vs. 0.4+/- 0.1, P< 0.01), while no significant difference of its expression was found between CRA tissues and their adjacent normal mucosae (P> 0.05). However,the PRL-3 mRNA levels of liver metastases (2.1+/- 0.8) in 12 cases and metastatic lymph nodes (3.3+/- 1.0) in 6 cases were significantly higher compared with the matched primary lesions, normal tissues and negative-lymph nodes (P< 0.01). There was significant relation of the expression of PRL-3 mRNA with the clinicopathological features including Dukes stage, invasion depth and metastasis (P< 0.05), but no relation with sex,tumor size,degree of differentiation was found (P> 0.05). Abnormal electrolysis band was found in 1 of 6 cases with liver metastasis by PCR-SSCP analysis.

CONCLUSIONPRL-3 gene plays an important role in tumor invasion and metastasis and may associated with carcinogenesis and development of CRC. There might exist some unknown mechanisms of overexpression and mutation of PRL-3 gene in CRC.