Relationship between labeling indices of KI‐67 and brdurd in human malignant tumors

Abstract

The relationship between labeling indices of Ki‐67 reactive antigen expressed by cycling cells and BrdUrd incorporated into S‐phase cells was investigated in 20 patients with malignant tumors. Both of the labeling indices varied greatly from patient to patient; the labeling index of Ki‐67 ranged from 37.5% to 1.9% with an average value of 16%, and the BrdUrd labeling index ranged from 23.4% to 1.6% with an average of 9.3%. The Ki‐67 labeling index was higher than the BrdUrd labeling index. In general, the values of the Ki‐67 labeling index were parallel to those of the BrdUrd labeling index, and the relation Y = 1.59X + 1.15 (r = 0.89) was obtained. In human solid tumors, therefore, the growth fraction can be easily estimated from the S‐phase fraction size, and vice versa. Copyright © 1988 American Cancer Society