Prognostic Significance of DNA and Apoptotic Index in Colorectal Carcinoma

ABSTRACT

Apoptosis is a distinct mode of cell death that is responsible for deletion of cells in normal tissues. Apoptotic cell death plays an important role in the proliferation and turnover of cells in various tumors. Apoptosis occurs spontaneously in malignant tumors, often markedly retarding their growth, and increased in tumors responding to irradiation, cytotoxic chemotherapy, heating and hormone ablation. Flowcytometric analysis of the cellular DNA content appears to be a useful clinical prognostic indicator in colorectal cancer. The relationship of apoptotic index(AI) and proliferative indices have being investigated. We analyzed the tumor DNA content and AI in 84 patients who underwent resection for colorectal cancer between January 1989 and December 1994 in order to evaluate the prognostic significance of apoptosis, DNA ploidy and index using in situ apoptosis detection method and flowcytometry. The mean value of AI was 32.4, and median value 21. In the cellular DNA, forty-two percent of the tumors were diploidy, fifty-eight percent aneuploidy. The mean value of DNA index(DI) was 1.38, G0/G1 72%, S phase fraction 21.7%, G2/M 6.3%, and proliferative fraction 28%. There was no significant difference between AI and tumor invasion, LN metastasis, DNA ploidy, DI.(p>0.05) There was no significance between overall survival and AI, DNA ploidy, DI. But patients who had tumors with low DNA index had a significantly longer disease free survival than high DNA index.(p<0.05) As a result, this study shows that AI is a less useful as prognostic factor and DNA index is a more important prognostic factor in patients undergoing surgery for colorectal cancer.