Autophagy indicators in oral squamous cell carcinoma

Autophagy plays an important role in maintaining cellular homeostasis. Dysregulation of autophagy has been linked to a number of diseases, including cancer. We retrospectively evaluated immunohistochemical expression of the autophagy markers LC3B and p62 and the autophagy regulator mTOR as an indicator of autophagy in 100 surgically resected primary oral squamous cell carcinoma (OSCC) samples and sought associations with various clinicopathological factors. The expression of all three proteins was significantly higher in malignant squamous cells than in benign squamous cells in the free mucosal margin adjacent to the OSCC. Male sex, higher tumour (T) stage, node (N) stage and tumour, node, metastasis (TNM) stage were significantly associated with high marker expression; age and histological grade showed no significant association. LC3B, p62 and mTOR expression were positively correlated with one another in OSCCs, and the correlation was significant for LC3B and mTOR as well as for LC3B and p62. Disease-free survival showed an inverse correlation with high mTOR expression. Our data suggest that autophagy inhibitors and mTOR inhibitors may have a therapeutic role in the treatment of OSCCs.