Imbalance between proliferation and apoptosis in the development of colorectal carcinoma

Abstract

To evaluate the relationship between cell proliferation and apoptosis in sporadic colorectal carcinogenesis, immunohistochemistry for proliferation-associated antigen Ki-67 and in situ end labelling for identifying apoptotic bodies were performed on paraffin sections from 59 adenomas and 22 carcinomas. These results were correlated with the expression of the proliferation and apoptosis modulators Bcl-2 and p53. Carcinomas showed increased proliferation and apoptosis compared with adenomas (PPPPPP0.05). Expression of Bcl-2 was associated with lower apoptotic rate in adenomas (P0.25), whereas p53 expression was correlated with higher proliferative rate in both adenomas and carcinomas (PPPP<0.005, respectively). These data suggest that the normal balance between proliferation and apoptosis is disturbed in colorectal carcinogenesis, both being increased, but proliferation occurs in excess. Bcl-2 and p53 may each play a role in modulating cell apoptosis or proliferation during the development of colorectal carcinoma.