Info
HER2
A molecular marker that shows whether the tumor has an excessive amount of HER2 protein. HER2 positive opens access to targeted biological treatments.
What it means
A protein that can be present in large amounts on the surface of some cancer cells. HER2 positive means that the tumor may respond to specific biological treatments that target this protein.
In short
A molecular marker that shows whether the tumor has an excessive amount of HER2 protein. HER2 positive opens access to targeted biological treatments.
Where you will see it
The immunohistochemistry (IHC) or FISH report. The IHC score can be 0, 1+, 2+, 3+. A score of 3+, or 2+ confirmed by FISH, = HER2 positive.
What it does not tell you on its own
HER2 on its own does not describe the stage of the disease and does not fully decide the treatment. It is interpreted together with ER, PR, Ki-67 and the clinical stage.
Questions for your doctor
- Am I HER2 positive or negative?
- What IHC score do I have?
- If I am HER2 positive, what biological treatment is available?
- Is confirmation by a FISH test needed?
Related terms
The terms below often appear alongside this one. Each definition is right here, so you do not have to look elsewhere.
- Immunohistochemistry
- A laboratory technique that uses antibodies to detect specific proteins in tumor cells. It helps establish the exact type of cancer and choose the right treatment, especially in breast, colon and lung cancers.
- Ki-67
- A protein present in cells that are actively multiplying. The Ki-67 value, expressed as a percentage, shows how fast the tumor cells are dividing. A high value indicates a more aggressive tumor.
- ER (oestrogen receptor)
- A protein present in some tumor cells that responds to the oestrogen in the body. ER positive tumors can be stimulated by oestrogen — but they can also respond to hormone therapy.
- Targeted therapy
- A drug treatment that selectively blocks specific molecules involved in the growth of cancer cells. Unlike chemotherapy, it affects healthy cells less. Examples: tyrosine kinase inhibitors, monoclonal antibodies.
Other terms in “Diagnosis”
Glossary definitions are written for patients by the OncoDots team and go through internal medical review. They explain terms; they do not establish a diagnosis and do not recommend a treatment.