Skewed Th17/Treg balance during progression and malignant transformation of oral submucous fibrosis

Objectives The aim of our study was to determine the impact of Th17/Treg imbalance on the progression and malignant transformation of oral submucosal fibrosis (OSF). Materials and Methods To assess Th17 and Treg expression, overall 52 peripheral blood samples from OSF, oral squamous cell carcinoma (OSCC) patients, and healthy donors were analyzed by flow cytometry. Thirty normal oral mucosa, 72 OSF, and 90 OSCC samples were analyzed by immunohistochemistry. Results In peripheral blood samples, in OSCC with OSF, Th17 and Treg expression were significantly higher than those in OSF and OSCC without OSF as confirmed by immunohistochemistry. During OSF progression, Th17 and Th17/Treg ratio showed an increasing trend, while Treg expression showed a decreasing trend. Treg expression was significantly higher in OSCC with OSF than in OSF and OSCC without OSF, whereas the Th17/Treg ratio was significantly lower in OSCC with OSF. Treg expression was significantly correlated with smoking and clinical stage. Th17/Treg ratio was significantly associated with tumor size, lymph node metastasis, and clinical stage. A low Th17/Treg ratio was significantly associated with poor prognosis. Conclusions Th17/Treg ratio is a potential diagnostic indicator for OSF occurrence and malignant transformation and was an independent prognostic factor for OSCC.