The short answer
Immunohistochemistry (IHC) is a lab test that uses special stains to find particular proteins in tissue. It helps identify a cancer's type and features that guide treatment.
IHC uses antibodies and stains to detect specific proteins in tissue.
It helps confirm the type and origin of a cancer.
It can reveal markers like hormone receptors or HER2.
Results help match a cancer to the right treatment.
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The full explanation.
A staining test
Immunohistochemistry, usually shortened to IHC, is a laboratory test that uses special stains to reveal particular proteins inside tissue. Antibodies — proteins that latch onto a specific target — are tagged with a dye and applied to a sample. Wherever the target protein is present, the stain lights it up under the microscope.
What it tells doctors
IHC helps answer several questions. It can confirm the type of cancer, offer clues about where a cancer started (useful when the origin is unclear), and detect specific markers such as hormone receptors or HER2 in breast cancer. These details often steer treatment.
Where it fits
A biopsy is how tissue is collected; IHC is one of the tests a pathologist runs on that tissue afterward. It is a routine, well-established part of analyzing many cancers.
Reading the results
IHC results are interpreted by a pathologist together with the tissue's appearance and any other tests. If your report mentions IHC or lists stained markers, your doctor can explain what those particular markers mean for your care.
Words to know
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Common questions
▸What is immunohistochemistry?
It is a laboratory test that applies antibodies, tagged with a visible stain, to a tissue sample. The stain lights up specific proteins, helping identify what kind of cells are present.
▸Why is it done?
IHC helps confirm the type of cancer, suggest where it started, and detect markers — such as hormone receptors or HER2 — that guide treatment decisions.
▸Is it the same as a biopsy?
No. A biopsy is how the tissue is collected. IHC is one of the tests a pathologist may run on that tissue in the lab.
▸How reliable is it?
IHC is a well-established, widely used technique. Results are interpreted by a pathologist alongside the tissue's appearance and other tests.
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