Does the Cancer Have Genes that are Not Normal?

HER2 is a gene (also called HER2/neu) that helps control how cells grow, divide, and repair themselves. About 1 out of 4 breast cancers has too many copies of the HER2 gene. The HER2 gene directs the production of special proteins, called HER2 receptors, in cancer cells. Read research about treatments for women with early-stage cancers that are HER2-positive.

Cancers with too many copies of the HER2 gene or too many HER2 receptors tend to grow fast. They are also associated with an increased risk of spread. But they do respond very well to treatment that works against HER2. This treatment is called anti-HER2 antibody therapy.

There are three tests for HER2-positive cancer:

• IHC test (IHC stands for ImmunoHistoChemistry)
  • The IHC test shows if there is too much HER2 receptor protein in the cancer cells.
  • The results of the IHC test can be 0 (negative), 1+ (negative), 2+ (borderline), or 3+ (positive).
• FISH test (FISH stands for Fluorescence In Situ Hybridization)
  • The FISH test shows if there are too many copies of the HER2 gene in the cancer cells.
  • The results of the FISH test can be "positive" (extra copies) or "negative" (normal number of copies).
• SPoT-Light HER2 CISH test (SPoT stands for Subtraction Probe Technology and CISH stands for Chromogenic In Situ Hybridization)
  • The SPoT-Light test shows if there are too many copies of the HER2 gene in the cancer cells.
  • The results of the SPoT-Light test can be "positive" (extra copies) or "negative" (normal number of copies).

Find out which HER2 test you had. This is important. Only cancers that test IHC "3+" or FISH or SPoT-Light "positive" will respond well to therapy that works against HER2. An IHC 2+ test result is called borderline. If you have a 2+ result, you can and should ask to have the tissue tested with the FISH or SPoT-Light test.