Expression of Bcl-xL, Bax, and p53 in primary tumors and lymph node metastases in oral squamous cell carcinoma

Disturbances in expression of apoptosis-associated proteins take part in the development and progression of many human malignancies. The aim of this study was the assessment of correlations among proteins involved in apoptosis-Bcl-xL, Bax, and p53-as well as relationships of these proteins with selected clinicopathological features in oral squamous cell carcinoma. Consequently, we examined by immunohistochemistry, using the avidin-biotin-peroxidase method, BclxL, Bax, and p53 expression in 56 samples of primary oral squamous cell carcinoma and in 22 matched pairs of primary and metastatic tumors. The evaluation of immunostaining of Bcl-xL, Bax, and p53 was analyzed in 10 different tumor fields, and the mean percentage of tumor cells with positive staining was evaluated. The significance of the associations was determined using Spearman correlation analysis and the chi-square test. We found positive Bcl-xL, Bax, and p53 immunostaining in 44.6%, 28.6%, and 58.9% of the studied primary tumors and in 63.6%, 45.5%, and 72.7% of lymph node metastases, respectively. Analysis of associations among studied proteins revealed positive correlation between Bcl-xL and Bax in primary tumors (P < 0.03, r = 0.307). Statistically significant relationship between p53 expression in primary oral cancers and its expression in lymph node metastases (P < 0.02) as well as increased expression of Bcl-xL, Bax, and p53 in metastatic sites compared with primary tumors could indicate an association of these proteins with oral cancer progression and development of metastases. Moreover, we suppose that knowledge about heterogeneity between primary and metastatic tumor might help to understand mechanisms of oral cancer progression.