What should you know about GIST immunohistochemistry?

Immunohistochemistry is performed on tissue, usually from a biopsy or a removed tumour. The laboratory applies antibodies that attach to selected proteins in cells. A coloured signal then shows whether a marker is present and where it appears in the tissue.

For a suspected GIST, the staining pattern is interpreted alongside the tumour’s appearance under the microscope, its location, imaging, and sometimes additional molecular testing. A marker result is not a diagnosis in isolation. The pathology report brings these pieces together and may help distinguish GIST from other tumours that can look similar.

Ask for the pathology report and have the treating team explain each reported marker in plain language. Confirm whether the sample was adequate, whether further testing is recommended, and how the findings affect surgery, targeted therapy, or monitoring.

Keep the report with your scan and biopsy records. If another specialist reviews the case, sharing the original pathology material may help them interpret the staining in context.

The test itself does not usually create an emergency. Contact your care team promptly for increasing pain, fever, redness or discharge at a biopsy site, ongoing bleeding, fainting, or new weakness after a procedure.

Ask which markers were tested, what the staining pattern shows, and whether the result supports GIST or another diagnosis. Ask whether molecular testing is needed, who will review the pathology, and how the result changes the proposed treatment.