Evidence for post-transcriptional down-regulation of the apoptosis-related genebcl-2 in human colorectal cancer

✍ Scribed by Berney, Christophe R.; Downing, Sean R.; Yang, Jia-Lin; Russell, Pamela J.; Crowe, Philip J.

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 453 KB
• Volume: 191
• Category: Article
• ISSN: 0022-3417
• DOI: 10.1002/(sici)1096-9896(200005)191:1<15::aid-path566>3.0.co;2-e

✦ Synopsis

This retrospective study was undertaken to investigate the expression of bcl-2 protein and messenger RNA in colorectal cancer (CRC). Immunohistochemical analysis using a monoclonal mouse antibody to the bcl-2 protein and in situ hybridization using a digoxigenin-labelled bcl-2 cRNA probe were carried out on formalin-®xed and paraf®n-embedded specimens from 53 colorectal adenocarcinomas, 27 liver secondaries, and 60 adenomas with various degrees of dysplasia. Normal human tonsil sections were used as positive controls. Expression of bcl-2 protein and of messenger RNA was evaluated semiquantitatively. The expression of bcl-2 protein was gradually and signi®cantly lost during the progression from moderately dysplastic adenoma to primary CRC (moderate/severe dysplasia: Mann±Whitney U-test, p=0.0001; severe dysplasia/ primary CRC: p=0.027), whereas the cellular expression of bcl-2 mRNA was gradually increased during the dysplasia/adenoma±carcinoma neoplastic sequence. These observations suggest that in a proportion of colorectal cancer cases, the bcl-2 proto-oncogene expression may be downregulated at a post-transcriptional level.