Affiliations: Department of Pathology, Unit 53, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030, USA. Tel.: +1 713 794 5625; Fax: +1 713 794 5664; E-mail: yungong@mdanderson.org. | [x] Department of Breast and Endocrine Surgery, Tokai University School of Medicine, Kanagawa, Japan | [y] Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
Abstract: Information on hormone receptor and human epidermal growth factor receptor 2 (HER2) is important for making optimal therapeutic decisions for breast cancer patients. Discordance in these biomarkers between primary breast carcinomas and corresponding metastases is well documented and may lead to changes in management option. The underlying mechanisms of biomarker discordance are complicated and multifactorial. Whereas biologic evolution, intratumoral heterogeneity, and subclonal selection may account for discordance, variations in sampling, processing, staining procedure and interpretation are the important contributory yet controllable factors. This article reviews the effects of different factors on the biomarker discordance, the clinical significance and the importance of standardizing methodology and interpretation criteria.
Keywords: Estrogen receptor, ER, progesterone receptor, PR, HER2, discordance, concordance
