Vector immunohistochemistry: what should you know?

Immunohistochemistry, often called IHC, uses antibodies to bind to selected proteins in a tissue section. A vector or detection component helps create a visible signal at the binding site, allowing a pathologist to examine the marker under a microscope. The colour, location and pattern of staining are considered alongside the tissue’s appearance.

This method can help classify a tumour, identify the likely tissue of origin or assess a marker that may influence treatment choices. A positive or negative stain is not interpreted in isolation. The result depends on the marker, sample quality, controls and the clinical context.

Ask which marker was tested, what the staining pattern shows and whether the result is considered reliable for your sample. IHC is usually performed on tissue already obtained during a biopsy or surgery; it does not usually require a separate procedure.

Keep the pathology report with your other records and ask whether additional stains, molecular tests or imaging are needed. Your oncology team can explain whether the finding changes diagnosis, staging or treatment planning.

The stain itself does not cause symptoms. Seek care for problems related to the biopsy or operation, such as increasing redness, swelling, drainage, fever, severe pain or bleeding that does not settle. Contact your team if the report is unclear or you do not know when results will be discussed.

Ask what the tested marker does, whether the staining is strong, weak, focal or absent, and how it fits with the diagnosis. Ask whether the sample was adequate and whether another test could change the interpretation.