High LC3 expression correlates with poor survival in patients with oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is a destructive disease with very poor prognosis and no effective treatment. Autophagy is a dynamic cellular process involved in various physiological processes and diseases including cancer that degrades cytoplasmic proteins and organelles. The role of autophagy in the pathogenesis of OSCC is not yet understood. Microtubule-associated protein light chains 3 (LC3) is a reliable autophagosome markers for monitoring autophagy. In the present study, LC3 expression was determined in a cohort of 90 OSCC samples by immunohistochemistry. The results were correlated with clinical and pathological characteristics of patients. High LC3 expression (N = 57; 63.3%) correlated with stage (P < .0001), tumor size (P < .0001), and lymph node involvement (P = .0003) and with an increased risk of death (P < .0001; hazard ratio, 3.59) in a univariate analysis. In the multivariate analysis adjusted for grade, stage, and alcohol, betel, and tobacco consumption, high LC3 expression retained statistical significance with regard to survival (P = .0043; hazard ratio, 2.99). The Kaplan-Meier survival curve also showed that high LC3 expression was significantly associated with poor overall survival (P = .0001). Elevated LC3 expression, which corresponds to increased level of autophagy activity, is a frequent event and an indicator of poor prognosis in human OSCC.