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Estrogen also mediates part of its proliferative action on normal breast through transactivation of the progesterone receptor (PR); progesterone is also a mitogenic stimulus for mammary epithelium.
The assessment of ER and PR status in tumors by immunohistochemistry has become standard of care in breast cancers, and is rapidly being incorporated as a biomarker for other tumors as well. This analysis provides clinicians with important prognostic information, and helps predict the response to endocrine therapy. Breast cancer patients whose lesions contain both ER and PR have the best probability of remission following hormonal therapy (approaching 70%) than the group of patients whose lesions contain either receptor alone (approximately 30%), or very low levels of both receptors (approximately 10%). It has been shown that tumors expressing ER and PR tend to be better differentiated and low-grade tumors, but this is not always the case. Cancer related survival in breast cancers is independently predicted by the status of ER and PR in some studies. Similarly, in the endometrium, ER negative status has been shown to be predictive of recurrence of low stage tumors, independent of tumor grade, while negative PR status is associated with a significant risk of lymph node metastasis independent of other clinicopathologic factors.
Veripath OncoDiagnostics offers ER and PR on routine archival material as part of the standard breast, ovarian, and endometrial cancer panels, but it can also be ordered individually. In addition to surgical resections, this laboratory has extensive experience in evaluating cancer-related biomarkers such as ER and PR in needle core biopsies, which facilitates preoperative risk stratification. Currently, we are using an automated image analysis system to quantitatively score percentage positivity and intensity grade finally reflected in a histoscore on each evaluation. For more information contact Dr Raheela Ashfaq at Veripath OncoDiagnostics at 214.645.7053 or Raheela.Ashfaq@UTSouthwestern.edu.
Selected references:
1. Aaltomaa S et al. Hormone receptors as prognostic factors in female breast cancer. Ann Med 23:643; 1991
2. Biesterfeld S et al. Rapid and prognostically valid quantification of immunohistochemical reactions by immunohistochemistry of the most positive tumor focus. J Pathol 185:25; 1998
3. Gehrig PA et al. Estrogen receptor status, determined by immunohistochemistry, as a predictor of the recurrence of stage I endometrial carcinoma. Cancer 86:2083; 2000
4. Iwai K et al. Prognostic significance of progesterone receptor immunohistochemistry for lymph node metatstases in endometrial carcinoma. Gynecol Oncol 72:351; 1999
5. Kieback DG et al. Improved prediction of survival in advanced adenocarcinoma of the ovary by immunocytochemical analysis and the composition adjusted receptor level of the estrogen receptor. Cancer Res 53:5188; 1993
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