Assessing the New American Society of Clinical Oncology/College of American Pathologists Guidelines for HER2 Testing by Fluorescence In Situ Hybridization: Experience of an Academic Consultation Practice.

Context .- Evaluation of HER2 gene amplification by fluorescence in situ hybridization (FISH) was changed by recent American Society of Clinical Oncology/College of American Pathologists (ASCO-CAP) guidelines. Objective .

Characterization of HER2 status by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC).

The use of human epidermal growth factor receptor type 2 (HER2) gene amplification and overexpression as a molecular predictive marker has become critically important for proper selection of breast cancer patients for treatment with targeted therapeutic agents such as trastuzumab, lapatinib, pertuzumab, and T-DM1. A high level of sensitivity and specificity of molecular tests for this alteration is desirable. The American Society of Clinical Oncology and College of American Pathology have jointly established consensus guidelines to standardize characterization of this alteration in breast cancers.