Bag-1 expression as a prognostic factor in tongue squamous cell carcinomas

Abstract

Objectives: To investigate the prognostic significance of the antiapoptotic protein Bag-1. In addition, the relationship between Bag-1 expression, other apoptosis-related and proliferative parameters.

Study design: Eighty-five randomly selected patients with T1 to T4 oral tongue squamous cell carcinomas (SCC) were studied.

Methods: Sections from diagnostic, formalin-fixed, paraffin-embedded specimens were stained immunohistochemically to detect Bag-1 protein.

Results: Bag-1 expression correlated positively with apoptosis-related parameters such as Bcl-2 expression (P =.001) and proliferation-related parameters including Ki-67, mean argyrophilic nucleolar organizer regions (mAgNOR), and the percentage of AgNOR (pAgNOR) (P =.0117, P =.0257, and P =.0008, respectively). Correlation with Bag-1 expression and T classification (P =.0362), N classification (P =.0284), and clinical stage (P =.0117) was also found. In addition, Bag-1 expression was associated with the carbohydrate epitopes H-antigen and Le (P =.0004 and P =.0011, respectively). No correlation was found between Bag-1 expression and p53 accumulation, Bax expression, or apoptotic index (AI). However, a combined score of Bcl-2 and Bag-1 expression was inversely associated with AI (P =.046). Patients with tumors expressing high Bag-1 values had a shortened disease-specific survival time when compared with those with low Bag-1 values (P =.0017). A two-parameter combination between Bag-1 expression and Bax expression or AI, respectively, revealed an enhanced prognostic potential (P <.0001) when compared with single parameters.

Conclusion: Correlation between Bag-1 expression and other biologic variables revealed that Bag-1 might be involved in several biologic processes including apoptosis and cell proliferation. The expression of Bag-1 protein, particularly in combination with Bax expression or AI, respectively, has prognostic value in oral tongue SCC.