The presence or absence of estrogen and progesterone receptors in the cytoplasm of tumor cells is of paramount importance in managing patients with breast cancer. Patients whose primary tumors are receptor positive have a more favorable course than those whose tumors are receptor negative. Receptors are of value in determining adjuvant therapy and for treatment of advanced disease. Up to 60% of patients with metastatic breast cancer will respond to hormonal manipulation if their tumors contain estrogen receptors. Fewer than 5% of patients with metastatic, estrogen receptor-negative tumors can be treated successfully in this fashion.

Receptor status is valuable not only in managing metastatic disease but also in helping select patients for adjuvant therapy. Adjuvant hormonal therapy (tamoxifen) with receptor-positive tumors and adjuvant chemotherapy with receptor-negative tumors improve survival rates even in the absence of lymph node metastases (see Adjuvant Systemic Therapy, below).

Progesterone receptors may be a more sensitive indicator than estrogen receptors of patients who may respond to hormonal manipulation. Up to 80% of patients with metastatic progesterone receptor-positive tumors improve with hormonal manipulation. Receptors have no relationship to response to chemotherapy.

The estrogen, progesterone, and HER-2/neu receptor status and proliferative indices of the tumor should be determined at the time of initial biopsy. This is performed on paraffin-fixed tissue by immunohistochemistry. HER-2/neu assessment in breast cancer by immunohistochemistry is appropriate for patients with tumors that score 3+. Fluorescence in situ hybridization (FISH) is recommended for women with 2+ immunohistochemistry scores to more accurately assess HER-2/neu amplification and provide better prognostic information. Receptor status may change after hormonal therapy, radiotherapy, or chemotherapy.

_{Konecny G et al: Quantitative association between HER-2/neu and steroid hormone receptors in hormone receptor-positive primary breast cancer. J Natl Cancer Inst 2003;95:142. Pubmed: 12529347}