PURPOSE: The laminin-5 γ2 chain plays an important role in cell migration during tumor invasion and tissue remodeling. Although this chain has been reported to be expressed in tumor-stroma interface of colorectal carcinoma, prognostic significance of its expression has not been elucidated in these tumors, so we investigated the clinicopathologic significance of Laminin-5 γ2 chain expression in colorectal carcinoma. METHODS: Laminin-5 γ2 chain expression was investigated immunohistochemically in 103 colorectal carcinoma patients with Stage II, III, and IV disease. The patients were categorized into three groups according to the number of immunopositive tumor cells in the sections containing the maximum diameter of the tumor as follows: +, less than 20 tumor cells were positive; ++, 20 to 500 tumor cells were positive; +++, more than 500 tumor cells were positive. RESULTS: Laminin-5 γ2 chain expression was observed in cytoplasm of tumor cells, especially those in the invasive front of the tumor penetration. Eighteen (17 percent) of tumors showed +, 60 (58 percent) showed ++, and 25 (24 percent) showed +++. The increased number of immunopositive tumor cells was significantly associated with synchronous liver metastasis (P = 0.048). The univariate (P = 0.036) and multivariate (P = 0.001) analysis of the patients' survival revealed that the prognosis became significantly poorer in patients with the increased number of immunopositive tumor cells. CONCLUSIONS: Increased laminin-5 γ2 chain immunoreactivity, suggesting a high invasive potential of tumor cells, was a significant poor prognostic indicator for the patients with colorectal carcinoma.
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