HER2 Breast

This test uses the Ventana PATHWAY anti-HER-2/neu antibody (clone 4B5) for the semi-quantitative detection of HER-2 antigen in sections of FFPE normal and neoplastic tissue. The test is FDA-approved with the indication as an aid in the assessment of breast cancer patients for whom Herceptin treatment is considered. Staining is performed according to the package insert. Scoring for breast cases is performed according to ASCO/CAP 2023 guidelines. HER2 is an oncogene that is over-expressed in a variety of cancers including some breast carcinomas. The expected breast cancer overexpression rate varies based on the grade and type of cancer. Known artifacts, such as edge artifact, tissue retraction and tissue crush may give the false impression of overexpression. Care should be taken to avoid assessing these areas, especially in needle core biopsies that generally harbor all of these artifacts.