Abstract: Objective To investigate the expressions of tumor suppressor gene FEZ1 and hypoxia inducible factor (HIF)- 1α in oral squamous cell carcinoma (OSCC), and their correlation with clinicopathological features and prognosis. Methods A total of 146 specimens of OSCC and 80 normal oral mucosa were used to detect the expressions of FEZ1 and HIF-1α by immunohistochemistry. Thirty specimens of fresh OSCC tissues, 30 samples of the paracancerous tissues and 30 normal mucosa tissues were also included in the study. The relationship between the expressions of FEZ1 and HIF-1α, the clinicopathological features and the prognosis of the patients were analyzed. Western blot assay was used to detect the expressions of FEZ1 and HIF-1α in 30 fresh OSCC tissues, 30 samples of the paracancerous tissues and 30 normal mucosa tissues. Results In OSCC tissues, the positive rate of FEZ1 protein (30.14%) was significantly lower than that in normal oral mucosa (81.25%), and the positive rate of HIF-1α protein (71.23%) was significantly higher than that in normal mucosa (12.50%，χ2=54.076 and 71.317, P < 0.01). There was a correlation between the expression of FEZ1 and clinical stage, tumor size and differentiation. The expression of HIF-1α was correlated with gender, lymph node metastasis, tumor size and differentiation. There was no significant difference in 5-year survival rate between positive and negative FEZ1 expression groups. The 5-year survival rate was significantly lower in HIF- 1α positive expression group than that of HIF- 1α negative expressiongroup (P < 0.05). The expression level of FEZ1 was decreased by the sequences in normal oral mucosa, paracancerous tissue and OSCC (P < 0.01), but the expression level of HIF-1α was increased in turn (P < 0.01). Conclusion FEZ1 and HIF-1α may be involved in the occurrence and progress of OSCC. The expressions of FEZ1 and HIF-1α can be used as a reference for the biological behavior of OSCC.

Key words: oral squamous cell carcinoma, FEZ1, hypoxia inducible factor-1α, immunohistochemistry, Western blot;
clinical features, survival analysis