Intratumoral Heterogeneity in Breast Cancer: A Case Report and Molecular Discussion

The emerging era of personalized medicine makes it increasingly important to consider intratumoral heterogeneity, which has been found in some breast cancer cases. However, its identification criteria, form of reporting, and subsequent effects on the clinical course of this disease remain controversial and not fully defined. Here, we report and discuss a case of breast invasive ductal adenocarcinoma with substantial intratumoral heterogeneity, discrepancy between Her2/neu immunostaining and in situ hybridization, and disparity between estrogen receptor status before and after neoadjuvant therapy.