BCL2 and BAX expression in hyperplastic and dysplastic rectal polyps.

ABSTRACT

BACKGROUND/AIMS: Members of the gene family that includes BCL2 and BAX are functionally antagonists in the apoptosis process and they have been observed in normal and neoplastic tissues. The aim of this study is to investigate the combined effects of BCL2 and BAX protein in normal mucosa, dysplastic and hyperplastic polyps of the rectum. METHODOLOGY: We studied BCL2 and BAX protein expression in 40 cases of adenomatous polyps all located in the rectum, with different dysplastic gradings, and the mean time in 10 cases of normal rectal mucosa. RESULTS: BCL2 expression was found more frequently in hyperplastic and in low dysplastic polyps with moderate and strong positivity compared to moderate and severe dysplasia. BAX expression was found in normal mucosa in hyperplastic and dysplastic polyps, the immunoreactivity was prevalently moderate and strong. CONCLUSIONS: These preliminary data suggest that BCL2 and BAX confirm a probably different role in apoptosis. Nevertheless, it is important to know the relation between the molecular pathways of apoptosis, the defective mismatch repair and the tumor suppressor genes associated with an increased mutation rate in cancerogenesis of the colorectum.