Bcl-xL overexpression and its association with the progress of tongue carcinoma

Apoptosis-related protein B-cell lymphoma-extra large (Bcl-xL) has a crucial role in the control of cell death through its inhibition of apoptosis. This study was designed to investigate the expression of Bcl-xL in relation to the development of tongue carcinoma and whether it has potential as a marker for the clinical diagnosis of tongue carcinoma and as a therapeutic target to evaluate the dynamic of tongue carcinoma progression. A statistical analysis of 100 cases oral tongue carcinoma tissue specimens were performed using pathological grading and clinical TNM staging, and 14 cases corresponding non-tumor tissues as control. The changes in Bcl-xL mRNA expression between different pathological grades and clinical TNM stages of tissue were analyzed by RT-PCR. Additionally, immunohistochemical SP method and Western blot assays were employed to detect changes in Bcl-xL protein expression in different tongue carcinoma tissues. The results showed the expression of Bcl-xL was significantly higher in tongue carcinoma tissues than in normal tongue tissues and was positively associated with the degree of differentiation and the clinical TNM staging, but negatively correlated with the degree of malignancy of the tumor. There was higher expression of Bcl-xL in oral tongue squamous cell carcinoma (OTSCC) tissues compared with oral tongue adenocarcinoma (OTA) tissues, but Bcl-xL expression in tissue with lymph node metastasis was significantly higher than that without lymph node metastasis. Thus, Bcl-xL overexpression may be closely related to the dynamic of the pathogenesis and development of tongue carcinoma. It may be a useful marker for clinical diagnosis and an aid to evaluating the efficacy of therapeutics in tongue carcinoma.