Apoptosis of colon cancer: comparison with Ki-67 proliferative activity and expression of p53

The role of apoptosis in colon cancer was investigated in terms of control of growth and expression on p53, using the nick-ended-DNA labelling method and immunohistochemistry. The apoptotic labeling index was highest in the T1 stage (24 cases), as was the proliferative activity, assessed in terms of the Ki-67 labeling index. Both labeling indices demonstrated similar overall incidence curves for the total 95 colon cancer cases, and examination of individual cases revealed a statistically significant correlation (P=0.01). However, neither index had any relation to p53. The results thus suggest that apoptosis in colon cancers has a linkage with proliferative activity that can be assessed by Ki-67 labeling, but is not regulated by the p53 system. This might contribute to the diversity of colon cancer growth.