Objective: To investigate the proliferating effect of estradiol benzoate on normal human breast tissue.
Methods: Three specimens of normal human breast tissue were implanted into nine 9-10-week-old intact female athymic nude mice which were randomly divided into group A, B and C. Each specimen was divided into three parts, and each part was implanted into mice of each group of three (A, B and C) respectively. Two weeks later, part of xenografts was taken out from group A as control group, and then group A, B and C were injected muscularly with 3, 6, 9 micrograms estradiol benzoate once daily, respectively. After therapy for 28 days, the grafts were taken out and expression of proliferating cell nuclear antigen (PCNA), estrogen receptor (ER) and proliferating receptor (PR) in grafts were examined using immunohistochemical method.
Results: Compared with control group, PCNA was increased in group B and C (P < 0.05), but in group A had no significant change. ER was gradually down regulated by 3, 6 and 9 micrograms estradiol benzoate (P < 0.05); however, PR was increasingly up regulated (P < 0.05).
Conclusions: Certain dosage of estradiol benzoate has proliferating effect on normal human breast tissue.