Review ArticleExpression Patterns of Biomarkers in Primary Tumors and Corresponding Metastases in Breast CancerKümler, Iben MD, PhD; Balslev, Eva MD; Knop, Ann S. MD, PhD; Brünner, Nils MD, MSc; Klausen, Tobias W.; Jespersen, Sofie S.; Nielsen, Signe L.; Nielsen, Dorte L. MD, MSc Author Information Department of Oncology, Herlev Hospital, Herlev Ringvej, Herlev, Denmark The authors declare no conflict of interest. Reprints: Iben Kümler, MD, PhD, Department of Oncology, Herlev Hospital, Herlev Ringvej 75, 2750 Herlev, Denmark (e-mail: [email protected]). Applied Immunohistochemistry & Molecular Morphology: January 2018 - Volume 26 - Issue 1 - p 13-19 doi: 10.1097/PAI.0000000000000380 Buy Metrics Abstract Tumor heterogeneity has been shown for several cancers including breast cancer (BC). Despite the fact that expression of tumor markers may change throughout the metastatic process, rebiopsies at the time of recurrence are still not performed routinely at all institutions. The aims of the study were to evaluate changes in biomarker profiles during the metastatic process and to investigate whether previous anthracycline or endocrine therapy given in the adjuvant setting could affect the biomarker profile in metastatic lesions. We investigated the expression pattern of ER, HER2, TOP2a, TOP1, p53, Bcl-2, and Ki-67 in 110 paired samples of primary BC and corresponding asynchronous metastases. We found discordant expressions in primary tumor and metastasis for all biomarkers, although only significant for Ki-67. Changes in the expression profile of the metastatic lesions would have altered treatment decisions in 14% of patients. We found no effect of previous anthracycline or endocrine therapy on the expression profiles. Our data confirm that discordant expressions of biomarkers are common in BC and often carry therapeutic consequences. This emphasizes the need for biopsies from metastatic lesions, even in cases where the localization of the metastatic process is not easily accessible. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.