Clinicopathologic significance of laminin-5 γ2 chain expression in squamous cell carcinoma of the tongue: Immunohistochemical analysis of 67 lesions

BACKGROUND. The laminin-5 γ2 chain plays an important role in cell migration during tumor invasion and tissue remodeling. METHODS. Laminin-5 γ2 chain expression in squamous cell carcinomas of the tongue in 67 patients with Stage II, III, or IVA,B (excluding the cases with distant metastasis) was examined immunohistochemically to determine its associations with the clinicopathologic features of each tumor. The predominant staining patterns were categorized as follows: A, few or no tumor cells were positive; B, part of the tumor nest periphery was positive; C, the tumor nest periphery was circumferentially positive; or D, almost all the tumor cells were positive. RESULTS. Laminin-5 γ2 chain expression was observed clearly in tumor cell cytoplasm. Of the 67 tumors examined, 6 (9%), 31 (46%), 19 (28%), and 11 (17%) showed staining patterns A, B, C, and D, respectively. With progression from staining pattern A to D, the number of immunopositive tumor cells increased significantly (P < 0.0001), and the tumor histology showed significantly more infiltrative growth (P < 0.0001) and poorer differentiation (P = 0.0021). Furthermore, both univariate (P = 0.0019) and multivariate (P = 0.0003; hazard ratio = 3.132) analysis of the patients' survival revealed that the prognosis became significantly poorer with progression from staining pattern A to D. CONCLUSIONS. Increased laminin-5 γ2 chain immunoreactivity, which may reflect a high invasive potential of cancer cells, is a factor indicative of a poor prognosis for patients with squamous cell carcinoma of the tongue.