Relationship between the thymidine labeling and Ki-67 proliferative indices in 126 breast cancer patients

Proliferative activity has been proposed as a prognostic and predictive marker for breast cancer; Ki-67 is one of the most frequently used markers to assess proliferative activity. In the current study, Ki-67 immunoreactivity was comparatively assessed, even in terms prognostic relevance, with 3H-thymidine labeling index as a reference standard for proliferation in 126 patients with stage I and II breast cancer. There was a significant but weak correlation between Ki-67 values and the 3H-thymidine labeling index (r = 0.19, P = 0.03). Analysis of variance showed that the mean 3H-thymidine labeling index values were not statistically different in terms of pathologic size (T1, T2, T3, T4), number of pathologically positive axillary nodes (neg. pos 1-3, pos > 3), and grading classes (1, 2, 3), but significantly and inversely correlated with estrogen receptor status (P = 0.033) and progesterone receptor status (P = 0.08). The Ki-67 values significantly correlated with N status (P = 0.041), ...