Intratumoral heterogeneity in breast cancer: A case report and molecular discussion

Introduction: Facing the emerging era of personalized medicine, it is increasingly important to consider the intratumoral heterogeneity. Intratumoral heterogeneity has been also described in breast cancer, although its identification criteria, form of reporting, and subsequent effects on the clinical course of disease are controversial and remain to be fully defined. Case presentation: Here, we report and discuss a breast invasive ductal adenocarcinoma with substantial intratumoral heterogeneity (Her2/neu and basal-like areas in molecular subtyping), discrepancy between Her2/neu immunostaining and insitu hybridization (+1 in immunohistochemistry versus Her2/neu gene amplificatied in dual color chromogenic in situ hybridization), and also disagreement between estrogen receptor status before and after neoadjuvant therapy (positive estrogen receptor changed to negative after treatment). Discussion: According to the current ASCO/CAP guideline, it is not required to report ki67 staining (which is necessary for molecular subtyping) and Her2 gene heterogeneity. Also, it does not address the important topic of molecular subtyping. In our opinion, the exact underlying mechanisms andprognostic consequences of intratumoral molecular heterogeneity and discrepant Her2/neu assessments are yet to be fully realized. We recommend including these subjects in the next update of the ASCO/CAP guideline in order not only to provide unified definitions for further trials, but also to aid clinicians in the practice of personalized medicine.

کلیدواژه ها:

breast ، estrogen receptor ، ErbB-2 ، genetic heterogeneity ، personalized medicine