Background The aim of this study was to conduct a comparative evaluation of the expression levels of autophagy markers and proteins of the mammalian target of rapamycin (mTOR) pathway in normal, margin and tumour tissues of patients with oral squamous cell carcinoma (OSCC). Materials and Methods Three regional specimens, including normal, margin and tumour tissues, were collected from 26 patients with OSCC. Western blotting, immunohistochemistry and immunofluorescence staining were performed to detect mTOR, eukaryotic translation initiation factor 4E‐binding protein 1 (4E‐BP1), p70 ribosomal S6 protein kinase (p70S6K) and the corresponding phosphorylated proteins, as well as the light chain 3 (LC3) and sequestosome‐1 (SQSTM1, also known as p62) autophagy indicators. Results LC3‐II, p62, mTOR, phospho‐mTOR, 4E‐BP1 and phospho‐4E‐BP1 were highly expressed in the margin and tumour groups. There were positive correlations between mTOR/phospho‐mTOR, mTOR/4E‐BP1, mTOR/phospho‐4E‐BP1, mTOR/p70S6K, LC3‐II/p62, LC3‐II/p70S6K, p62/4E‐BP1 and p62/phospho‐4E‐BP1 in normal group, while LC3‐II/p62, LC3‐II/mTOR, LC3‐II/4E‐BP1, LC3‐II/phospho‐4E‐BP1, phospho‐4E‐BP1/mTOR, phospho‐4E‐BP1/4E‐BP1 and p62/4E‐BP1 showed positive relationships in margin group; however, in tumour group, only mTOR/phospho‐mTOR, 4E‐BP1/phospho‐4E‐BP1 and phospho‐mTOR/p70S6K showed positive correlations. Conclusion The study suggests that autophagy is impaired in patients with OSCC and impaired autophagy and the mTOR pathway are simultaneously activated in OSCC cells.

Background: Tumor recurrence is one of the major problems that affect the postoperative efficacy of oral squamous cell carcinoma (OSCC) treatment. Autophagy is known to have a dual-sided effect on tumors. However, studies on autophagy and prognosis are limited. The purpose of this study is to analyze the relationship between autophagy and OSCC recurrence. Materials and methods: 72 patients with OSCC were followed for 5 years after curative surgery. Tissue specimens from each patient were divided into tumor, normal, and marginal groups. Autophagy protein expression was assessed by western blotting and immunofluorescence. Statistical significance was evaluated using the chi-square test. The Kaplan-Meier method was employed to construct a survival curve, and the log-rank test was used to compare survival rates. Cox regression was utilized to describe independent prognostic risk factors. ROC analysis was performed to evaluate the utility of p62 and LC3II expression in assessing OSCC recurrence. Results: Correlations were observed between survival rates and T stage (p = 0.00439), lymph node metastasis (p < 0.001), tumor differentiation (p = 0.00423), and changes in p62 expression (p < 0.001). Multivariate analysis showed lower p62 protein expression in the tumor group compared to the normal group with a higher risk of recurrence (RR = 3.713), and lower p62 protein expression was found in the marginal group compared to the tumor group, with a lower risk of recurrence (RR = 0.170). Conclusion: Expression of p62 protein is one of the important factors influencing relapse in OSCC patients and can be used as an early predictor of OSCC relapse.