Study of antiapoptotic gene of oral carcinoma by using Bcl-2 oncogene.

The present study was addressed to find out the expression of Bcl-2 proto-oncogene in tumor tissue derived from 24 patients with malignant oral carcinoma and oral mucosa from the same patients served as control and showed a cytoplasmic pattern of Bcl-2 immunoreactivity in basal cell layer. Fourteen of 24 (58.3%) of oral carcinoma and four adenocystic carcinoma expressed positive Bcl-2 oncogene. Well-differentiated squamous cell carcinoma showed absence of immunoreactivity. No statistically significant correlation could be demonstrated between Bcl-2 immunoreactivity and the age or sex of the patients, tumor size, and lymph node metastasis. A direct correlation between Bcl-2 immunoreactivity in G2 and G3 was statistically significant (P < 0.05). Patients with absence of or low (scores 0 or 1) Bcl-2 immunoreactive tumors manifested poorer overall survival rate in comparison with patients with moderate or high (scores 2 and 3) Bcl-2 expression, but the difference was not statistically significant. Tumors exhibited three different expressions of Bcl-2 (weak, moderate, and strong positive), compared to the mucosa of some patients affected by these tumors. No correlation was found between the histopathology of the tumors, mucosal expression, and degree of Bcl-2 expression. We propose from this study that overexpression of Bcl-2 proto-oncogene acts as a strong antiapoptotic in both squamous cells and adenocystic carcinoma may be an important molecular event on oral carcinoma to make these tumors resistant to radiotherapy and chemotherapy.