Expression of the apoptosis related genes in colorectal cancers

Background. The size of a renewing cell population is dependent not only on cell proliferation, but also on apoptosis. The transformation of colorecta l epithelium to carcinomas was reported to be associated with a dramatic in hibition of apoptosis. To understand the molecular events in such abnormal apoptosis, we have tested the expression of several apoptosis related genes , including interleukin-l beta converting enzyme (ICE), bcl-2, and bar-alph a, and the cleavage of the poly(ADP-ribose) polymerase (PARP) by the caspas es in colorectal cancers. Methods. Expression of the genes mentioned above were estimated by RT-PCR w ith fluorescent-labelled gene-specific primers. The PCR products were analy zed by the DNA sequencer ABI 373 with GENESCAN 672 software. Results. ICE and bcl-2 were overexpressed in colorectal cancer tissues, as compared with normal tissues. The digestive form of the PARP was more in co lorectal cancer tissues than in normal epithelium. Bax-alpha was expressed in both normal and cancer tissues without significant difference. Conclusions. Caspases appear to be increased in colorectal cancer tissues. Overexpressed bcl-2 may help to prevent cells from apoptosis induced by cas pases in colorectal cancers.