PRL-3 Expression in Primary Colorectal Cancer

ABSTRACT

PURPOSE: Overexpression of the protein tyrosine phosphatase (PRL-3) is elevated in liver metastases derived from colorectal cancer. We examined PRL-3 expression in the primary lesion of colorectal cancer patients and investigated its relation to clinicopathological features. METHODS: A total of 63 randomly selected patients who underwent surgical resection for colorectal cancer between May 2001 and June 2005 at our hospital were investigated. Formalin-fixed and paraffin-embedded specimens from colorectal cancer patients who underwent surgical resections for primary tumors were collected. The expression of PRL-3 was detected by immunohistochemistry and the relation with age, sex, primary tumor size, tumor cell differentiation, depth of invasion, microscopic lymph node metastases, vascular invasion, numbers of lymph node metastases, postoperative stage, and postoperative survival time were analyzed. RESULTS: A total of 16 of the 63 colorectal cancer patients were detected with liver metastases during the follow-up periods. Liver resection was performed for those liver metastases patients. Five patients developed lung metastases after liver resection. PRL-3 expression was detected in 46 colorectal cancer patients. Fourteen patients with lymphatic invasion had positive expression of PRL-3 that was significant (P=0.042). The incidence of PRL-3 expression in the T stage was significant (P=0.019). Moreover, PRL-3 expression was closely associated with liver metastases (P=0.048). CONCLUSIONS: These results indicate that an investigation of PRL-3 expression in primary colorectal cancer lesions may contribute to the detection of occult liver metastases and to a differentiation between postoperative management strategies.