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HER2-Positive Breast Cancer

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Getting a Diagnosis continued...

The IHC test (immunohistochemistry) checks for how much HER2 protein is in a sample of breast cancer tissue.

Three other tests check to see if there are too many HER2 genes in the cancer cells:

  1. FISH test (fluorescence in-situ hybridization)
  2. SPOT-Light HER2 CISH test (subtraction probe technology chromogenic in-situ hybridization)
  3. Inform HER2 Dual ISH test (inform dual in-situ hybridization)

Sometimes the results of one test aren't clear, and your doctor may order another type of test.

Questions for Your Doctor

  • How are you sure my cancer is HER2 positive?
  • Where exactly is my cancer?
  • What stage is it?
  • What are my treatment options, and what do you recommend?
  • Should I have targeted treatment?
  • How quickly do I need to start treatment?
  • How will treatment make me feel?
  • Will I be able to work?
  • Do I need to have my breast removed?
  • Is my treatment covered by insurance?
  • What if my cancer doesn’t respond to treatment?


It's important to find out if your breast cancer is HER2-positive, because it makes a difference in how you treat it.

HER2-positive cancer doesn't respond well to hormone treatment used for some breast cancers, but there are drugs that target the HER2 protein and greatly lower the risk of the cancer coming back. These drugs aim to kill cancer cells without killing healthy cells. They are called targeted treatments, and in the case in of HER2-positive cancer, they stop or block the HER2 protein from helping cancer cells to grow.

Herceptin (trastuzumab) is usually the first treatment your doctor will recommend. It's often followed by surgery and chemotherapy.

Herceptin itself has far fewer immediate side effects than chemotherapy. There is usually no nausea or hair loss. In rare cases, there may be heart or lung problems. Talk to your doctor about side effects. Scientists are still studying how long women should take Herceptin to get the most benefit. 

Tykerb (lapatinib) may be an option if Herceptin doesn't work. It's given to women whose breast cancer has spread. Possible side effects include diarrhea, nausea, vomiting, rash and fatigue, and in rare cases, liver and lung problems.

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