Abstract: Objective: To investigate the expression of microRNA-21 in oral squamous cell carcinoma and its correlation with prognosis. Methods: 98 cases of oral squamous cell carcinoma tissue and normal tissue samples were selected. Meanwhile, mucosa of 50 cases of non-cancer patients was selected. Total RNA was isolated from specimens, respectively. The relative expression levels of microRNA-21 in oral squamous cell carcinoma and normal mucosa were detected by RT-PCR. Its correlations with clinicopathological features and prognosis were analyzed by Kaplan-Meier method. Results: The relative expression level of microRNA-21 in oral squamous cell carcinoma (2.37±1.01) was significantly higher (P<0.05) than normal mucosa (0.97±0.08) and non-cancer patients mucosa (0.94±0.07). The expression of microRNA-21 was not correlated with sex, age, tumor location, tumor size and TNM stage, but significantly correlated with the degree of differentiation and lymph node metastasis (P<0.05). All patients were divided into high and low expression groups according to the median value of microRNA-21 relative expression (2.41). The median survival of patients was 38 months in high expression group, while 44 months in low expression group, and the difference was statistically significant (P<0.05). Conclusion: The expression level of microRNA-21 was elevated in oral squamous cell carcinoma, which was correlated with the degree of differentiation and lymph node metastasis, and affected the prognosis of patients.

Key words: Oral squamous cell carcinoma, MicroRNA-21, Prognosis