Expression of autophagy-related markers at the surgical margin of oral squamous cell carcinoma correlates with poor prognosis and tumor recurrence

Oral squamous cell carcinoma (OSCC) is the sixth most common cancer worldwide, and is associated with poor prognosis. Autophagy is a programmed cell survival mechanism involved in physiologic processes and various diseases including cancer. However, the relationship between autophagy and cancer is controversial. Several studies have claimed that the expression of autophagy-related proteins, namely microtubule-associated protein light chain3 (LC3) and p62/SQSTM1 (p62), is associated with poor prognosis in OSCC. In this study, we evaluated the expression of the autophagy-related markers LC3A/B and p62 by immunohistochemistry in 71 OSCC patient samples, especially focusing on surgical margins. Results were correlated with clinical characteristics. The expression of LC3A and LC3B was correlated with tumor recurrence and poor overall survival based on multivariate analysis, whereas the expression of p62 was correlated with only tumor recurrence and not prognosis. Thus, we suggest that the expression of autophagy-related markers at the surgical margins might be an indicator of local recurrence and poor prognosis in human OSCC. These results will aid in the development of new therapeutics and diagnostics for OSCC.