Expression of PRL-3 Phosphatase in Human Gastric Carcinomas: Close Correlation with Invasion and Metastasis

Abstract

Objective: High expression of PRL-3, a protein tyrosine phosphatase, has been reported to be associated with metastasis of colorectal carcinoma. The aim of this study is to investigate the significance of PRL-3 expression in tumor progression and metastasis of gastric carcinoma. Methods: The levels of PRL-3 mRNA expression in 8 gastric cancer cell lines were examined by RT-PCR. Ninety-four human gastric carcinomas and 54 matched lymph node metastases were employed in this study. The expression of PRL-3 was detected by immunohistochemistry and the relationship with clinicopathological parameters was analyzed. Results: The expression of PRL-3 mRNA was clearly detected in 7 of 8 gastric cancer cell lines (87.5%) by RT-PCR. In tumor samples, PRL-3 expression was detected in 68% of primary gastric carcinoma (with nodal metastasis 81.5%, without nodal metastasis 50%; p = 0.004). The incidence of PRL-3 expression in lymph node metastasis was significantly higher than that in primary gastric cancers (p < 0.001). Moreover, PRL-3 expression was closely associated with lymphatic invasion (p = 0.002), extent of lymph node metastasis (p = 0.002) and tumor stage (p = 0.045). Conclusions: These results strongly suggest that PRL-3 expression may play a significant role in invasion and metastasis of gastric carcinoma. PRL-3 might be a novel molecular marker for aggressive gastric cancer.