Expression of Ki-67 and Bcl-2 biomarkers in normal breast tissue from women of reproductive age treated with raloxifene

Abstract

To evaluate the effect of raloxifene on antigen expression of Ki-67 and Bcl-2 in normal breast tissue. A randomized, double-blind study was conducted with 40 premenopausal women aged 18-40years who had been diagnosed with fibroadenoma of the breast. The patients were divided into two groups: Group A (placebo, n=20), and Group B (raloxifene 60mg, n=20).The medication was taken for 22days initiating from the first day of the menstrual cycle. An excisional biopsy was performed on the 23rd day. At the time of biopsy, a sample of normal breast tissue was collected to evaluate protein expression of Ki-67 and Bcl-2. The Student's t test and Chi-square test were used for statistical data analysis and the significance level was established at 5%. The mean percentage of nuclei stained for Ki-67 was 22.16±1.91 (p<0.001) and 2.161±0.181 in the control group and the raloxifene group. The expression of Bcl-2 was similar in both groups (p=0.8888). Raloxifene treatment significantly reduced antigen expression of Ki-67, but failed to have any significant results on the Bcl-2 expression. Further studies are warranted to evaluate the mechanism of raloxifene on apoptosis in normal breast tissue.