Ki-67 Expression Level Is Not a Significant Prognostic Factor in Korean Diffuse Large B-Cell Lymphoma.

The cell proliferation rate of tumors from patients with non-Hodgkin’s lymphomas has been shown to correlate with survival in previous studies. The aim of this study was to evaluate the independent prognostic value of Ki-67 expression level and the significance of cell proliferation rate as an outcome predictor. To this end, we reviewed the hospital case records and histopathological materials of 92 patients diagnosed with diffuse large B-cell lymphoma in a single center. The cell proliferative rate was expressed as percentage of Ki-67 positive cells (Ki-67 labeling index). All patients were available Ki-67 expression level. High Ki-67 labeling index was defined as nuclear Ki-67 expression in ≥ 70% of malignant cells. A cutoff point of 70% was used because this divided the group of cases into two subgroups of similar size (Ki-67 labeling index < 70, n = 46, Ki-67 labeling index ≥ 70, n = 46). The median age was 57 years (range, 15 to 83 years). The median follow-up time was 14 months. Sixty-nine (75%) patients were treated R-CHOP regimen initially and 13 (14%) patients were CHOP regimen. In a univariate analysis, age (p =.003), performance (p =.001), serum LDH (p =.020) were significant prognostic factors for overall survival. But Ki-67 had no statistical significance (p =.554). Multivariate analysis used Cox’s multivariate regression model revealed that serum LDH (relative risk estimate 6.7; 95% confidence interval, 1.5, 30.5), age (relative risk estimate 7.0; 95% confidence interval, 1.9, 26.4) were independent prognostic factors for overall survival. Taking all the results into consideration, it seems that Ki-67 expression level has no significance as outcome predictor in Korean diffuse large B-cell lymphoma.