Discordance in Human Epidermal Growth Factor Receptor 2 (HER2) Phenotype Between Primary Tumor and Circulating Tumor Cells in Women With HER2-Negative Metastatic Breast Cancer

Abstract

HER2 discordance between primary tumor and CTCs was observed in 18.8% of patients and was associated with histologic type, hormone receptor status of the primary tumor, and CTC number. The clinical utility of CTCs as liquid biopsy to assess tumor heterogeneity of metastatic disease and guide treatment decisions must be evaluated in prospective randomized trials.