Expression of Progesterone and Androgen Receptors in the Breast of Premenopausal Women, Considering Menstrual Phase.

BACKGROUND: Progesterone and androgens are important for normal development and tumorigenesis of the breast.

PATIENTS AND METHODS: Breast tissue samples from 49 premenopausal women were obtained. The progesterone receptors (PRA, PRB, PGRMC1 and PGRMC2) and the androgen receptor (AR) were determined in malignant and benign breast tumors and control tissues.

RESULTS: The PRB and AR mRNA levels were highest in tumors. PGRMC1 and PGRMC2 mRNA levels were higher in malignant tumors compared to their paired normal tissues. PRA protein showed most immunostaining in benign tumors. PRB immunostaining varied according to menstrual phase. AR immunostaining was highest in the glands of malignant tumors.

CONCLUSION: Progesterone and androgen receptors are differently regulated in tumors compared to normal breast tissues. A malignant breast tumor could appear PR-negative if collected in the luteal phase, but positive in the follicular phase. This finding may have clinical implications.