Status of estrogen and progesterone receptors in various phases of the menstrual cycle in breast cancer.

BACKGROUND Expression of hormone receptors is routinely evaluated in predicting tumor response to hormone therapy in breast cancer patients. Normal female genital organs show cyclic changes in the expression of estrogen and progesterone receptors. This study was designed to assess variations in estrogen and progesterone receptor expression rates in breast cancer patients, who were operated in different phases of the menstrual cycle. METHODS From 2001 through 2004, 161 premenopausal patients with breast cancer, who were operated on, were enrolled into this study. Immunohistochemistry for the expression of estrogen and progesterone receptors was performed on their tumor paraffin blocks, using antibodies against estrogen and progesterone receptors. RESULTS Estrogen receptor expression was seen in 24 out of 30 cases (80%) in early luteal phase, which was significantly higher than that of those operated in early follicular (53%), late follicular (51%) and late luteal (49%) phases (P < 0.05). Progesterone receptor expression also showed a rising trend in the early luteal phase (87%), as compared with the other phases (P = 0.09). CONCLUSION Expression of estrogen/progesterone receptor shows cyclic changes in breast cancer patients, being highest in the early luteal phase of the menstrual cycle. This variation implies that this phase of the cycle could be the golden time for evaluation of estrogen/progesterone receptor status.