Comparison of Progranostic Receptors in Primary Breast Cancer and Nodal Metastases

Comparison of Progranostic Receptors in Primary Breast Cancer and Nodal Metastases

October 1, 2012  |  Research

Authors: Shannon K. Rathke, MD | Alexander C. Mackinnon, Jr., MD, PhD | Zainab Basir, MD
Department of Pathology, Medical College of Wisconsin, Milwaukee, WI

Abstract

Background: Breast cancer treatment is guided by assessment of estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor 2 (HER2). There is limited research on comparison of these receptors in primary tumors versus their lymph node metastases. If receptor expression were different, it could guide changes in therapy. Our aim is to determine if there is a significant change in receptor expression in lymph node metastases compared to primary tumors.

Design: All patients having breast cancer with lymph node metastases at our institution between January 2008 and June 2011 were identified. Tissue microarrays (TMAs) were constructed when possible and remaining cases were stained individually. Immunohistochemistry (IHC) for ER, PR and HER2, and FISH for HER2 were performed on lymph node metastases. HER2 IHC was scored from 0 to 3+. HER2 FISH was positive if the ratio was >2.2. Results were compared with those of the primary tumors.

Results: 122 cases of breast cancer with lymph node metastases were obtained; 30 cases (25%) showed receptor changes. 4 cases (3.3%) showed expression changes in more than one receptor, 2 with PR and HER2 changes and 2 with ER and PR changes.

Conclusion: Changes in receptor expression in lymph node metastases when compared to the primary tumors do occur. The percentage of cases with changes in prognostic receptor expression warrants attention. This phenomenon may indicate that repeat testing for ER, PR, and HER2 on lymph node metastases is indicated to guide treatment and to explain therapy failure in patients with metastatic disease.

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