MicroRNA-mediated extracellular matrix remodeling in squamous cell carcinoma of the oral cavity.

BACKGROUND: We evaluated microRNAs and extracellular matrix component profiles in squamous cell carcinoma of the oral cavity (OSCC) in comparison to healthy mucosa. METHODS: Retrospective study investigating 64 microRNAs related to oncogenic process and to constituents of the extracellular matrix. We also performed immunohistochemical assays for molecules involved in the same biological processes. RESULTS: High expression of miR-21-5p (p < 0.001) and miR-106-5p (p < 0.001) and low expression of miR-320a (p = 0.001) and miR-222-3p (p = 0.001) were predictors of malignancy. Individually, miR-21-5p exhibited the best statistical performance (area under the curve = 0.972; 95% confidence interval: 0.911-1.000) in the differentiation between tumor tissue and healthy mucosa. Moreover, tumor sample showed increased expression of MMP-2, MMP-9, α-laminin, and ß-laminin in tumor-related fibroblasts and lower continuity of type IV collagen in the basement membrane. CONCLUSION: The present study demonstrates the biological effects of microRNAs on the carcinogenesis of OSCC as well as the intense modification of the tumor microenvironment.