Either a test called an immunohistochemistry (IHC) test or fluorescence in situ hybridization (FISH) test is used to find out if cancer cells have a high level of the HER2 protein.

Apr 28, 2022 · If you’ve been diagnosed with breast cancer, an IHC test can tell you if your cancer is HER2-positive. Keep reading to learn more about this test, when it’s used, and how it’s done.

Mar 3, 2025 · However, the IHC test may indicate that some HER2 protein is present but the results are just below the threshold for a HER2-positive cancer. In this situation, Dr. Haddad says it’s common to test again with FISH to conclusively determine whether the tumor is HER2 negative or positive.

Jun 7, 2023 · HER2 IHC assays were designed to distinguish high levels of protein over-expression due to gene amplification from those that lack over-expression and not to accurately detect and distinguish protein levels in the lower range of expression.

What to know about HER2 status in breast cancer diagnosis and treatment, including what HER2-positive, HER2-negative, and HER2-low mean.

Sep 20, 2022 · IHC testing typically comes first because it’s more affordable and faster than FISH, but FISH is considered more accurate. What do the test results mean? Results from IHC testing for HER2 fall within three ranges: 3+ (HER2-positive): Breast cancer cells …

May 15, 2024 · The IHC test is the most common way for your doctor to find out if your breast cancer is fueled by hormones or by a protein called HER2. Most breast cancers grow in response to estrogen.

2 days ago · Human epidermal growth factor receptor 2 (HER2; encoded by ERBB2) testing has been a cornerstone of patient selection for HER2-targeted therapies, principally in breast cancer but also in several ...

HER2 testing can be performed by either immunohistochemistry (IHC), or in situ hybridization (ISH) using either fluorescent (FISH), chromogenic (CISH) or silver (SISH) detection methods.

Jul 10, 2024 · By assessing the level of HER2 expression, scored from 0 to 3+, IHC can identify patients with high HER2 levels. 0: No HER2 protein overexpression is detected. The cancer is considered HER2-negative. 1+ (Score of 1): A small amount of HER2 protein is present, but it’s still considered HER2-negative.