Her2 Positive Breast Cancer

Determining the exact HER2 status of women with breast cancer is fundamental for further therapy decisions.

HER2 status in breast cancer patients is currently tested first by determining if the HER2 protein is over-expressed. This is done using the immunohistochemistry (IHC) tissue diagnostic method, which detects HER2 receptors on the cell surface.

Should the IHC results be equivocal, the next step is to test for the patient’s HER2 gene status. To do this, pathologists use the in situ hybridization (ISH) method to measure the number of copies of the HER2 gene in the nuclei of tumor cells. Knowing this gene amplification status helps pathologist to determine HER2 positivity in ambiguous cases.