Comparison of Tumor Biomarkers in Primary Breast Carcinoma and Paired Metastases
Gregory Moses, Yan Peng, Yisheng Fang, Sunati Sahoo, Venetia Sarode. UT Southwestern Medical Center, Dallas, TX
Background: Tumor biomarkers such as ER and HER2 may change between primary breast cancer and subsequent distant metastases. This change may have therapeutic implications. Loss of ER is an established predictor of poor response to endocrine therapy. The aim of this study is to determine changes in ER, PR, HER2, Ki-67 and p53 between primary breast cancer and metastases.
Design: Forty-six female patients with paired primary breast carcinomas and distant metastases were identified from the UT Southwestern Medical Center pathology files and analyzed retrospectively. Tumor biomarkers (ER, PR, HER2, Ki-67, and p53) were performed prospectively at the time of diagnosis using routine immunohistochemistry and image analysis. All IHC positive HER2 was confirmed by FISH. Biomarker expression was compared on primary and metastatic tumor pairs.
Results: In the primary tumors, luminal B subtype was most common, 25 of 46 (54.3%), followed by triple-negative (17.4%), luminal-HER2 (15.2%), HER2 (10.9%), and luminal A (2.2%). Sites of metastasis were skin (13), bone (11), distant lymph nodes (10), serous cavities (8), lung (5), liver (3), gynecologic tract (3), and brain (2). Comparison of tumor markers between paired primary tumors and metastases are shown in the table.