Actinin-4 Expression Predicts Poor Disease-free Survival and Correlates with Delayed Lymph Node Metastasis in Patients with Completely Resected Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma is generally characterized by poor prognosis, and biomarkers are needed for development and selection of therapy. The purpose of this study was to assess expression of actinin-4, which has been implicated in cancer invasion and metastasis, to determine its viability as a prognostic indicator in oral squamous cell carcinoma. Clinical factors and tumor samples immunohistochemically stained for actinin-4 were retrospectively investigated in 55 patients who underwent curative surgery for oral squamous cell carcinoma. Overall survival and disease-free survival were estimated by Kaplan-Meier analysis. Significant differences were detected using the Pearson's chi-square and Fisher's exact tests. Univariate and multivariate analyses were performed with the Cox regression model. No association was found between expression of actinin-4 and clinical factors, including age or sex, or histopathological factors, including vascular invasion, lymphatic invasion, stage, mode of invasion, or histological atypicality. Expression of actinin-4 showed a positive correlation with delayed cervical lymph node metastasis. Disease-free survival was significantly lower in patients who were positive for expression of actinin-4 (p=0.010); overall survival showed no difference between patients with or without expression of actinin-4, however. The results revealed that actinin-4 was an independent prognostic factor for disease-free survival. Expression of actinin-4 showed a 73% sensitivity and 68% specificity for prediction of delayed cervical lymph node metastasis. In conclusion, actinin-4 may potentially be a useful biomarker for prediction of delayed cervical lymph node metastasis.