HER - 2 / neu Test

This test is recommended for a person who is diagnosed with breast cancer. This test helps determine if a tumour is positive for HER2/neu. This test is conducted to see if the patient may benefit from the treatment with trastuzumab, which is a drug that was created to fight HER2. This test also acts as a prognostic marker to see how aggressive the tumour is. This way, the doctor is able to come up with a suitable treatment plan for the patient and he will be able to understand a tumour better. This test is prescribed along with estrogen and progesterone hormone receptor status tests (ER and PR).

You don’t have to do any special preparation for this test. You must let your doctor know about all your medications that you are taking currently and your medical history. It will be beneficial if you could take someone along with you for the test.

If the results are 0-1+, it means that the HER2 level is normal. Therefore, the tumour is HER2 negative. If the results are 2+, it means there is some overexpression of HER2. Your doctor will further conduct a FISH test to confirm the HER2 status. If the results are 3+, it means that the HER2 is higher than normal. Therefore, the tumour is HER2 positive.

A biopsy is performed to collect the sample of a tumour. This sample is tested either using immunohistochemistry (IHC) method or the Fluorescence in situ hybridization method (FISH). In immunohistochemistry, it measures the amount of HER2 protein present in the cancerous cells. In FISH, it looks at the copies of the HER2 gene in the cancerous cells.