What should you know about applied immunohistochemistry and molecular morphology?

A pathologist first examines the architecture of a tissue sample and the shape and arrangement of its cells. Immunohistochemistry then uses labelled antibodies to show whether selected proteins are present, absent, or distributed in a particular pattern. Molecular tests may look for changes in genes, RNA, or other cellular features. The results are interpreted together rather than as isolated labels.

This combined view can help distinguish tumour types that look alike under a microscope, suggest where a cancer began, refine a subtype, or identify a marker relevant to treatment. A marker result does not establish the whole diagnosis by itself; the sample quality, clinical history, imaging, and other laboratory findings can change its meaning.

Review the final pathology report with the clinician who ordered the biopsy. Ask which findings establish the diagnosis, which are supportive, and whether any result is indeterminate. Check whether there was enough suitable tissue for all planned tests and whether additional staining, molecular testing, or review by a specialist pathologist is pending.

Keep a copy of the complete report, including later addenda, because biomarker results may arrive after the main diagnosis. Before treatment begins, confirm how the findings affect the proposed plan and whether another tissue sample would materially change a decision. Do not interpret a positive or negative stain without the report's context and the pathologist's conclusion.

These laboratory findings do not themselves cause symptoms. Contact your care team promptly if you are waiting for results and develop a new or worsening symptom, or if the biopsy site becomes increasingly red, swollen, painful, or starts draining. Seek urgent medical help for heavy bleeding that does not stop with firm pressure, severe shortness of breath, chest pain, fainting, or rapidly worsening swelling after a biopsy.

Which tissue features and markers support my diagnosis? Were any results uncertain or conflicting? Is more testing needed before choosing treatment? Was the sample adequate, and could treatment decisions require a repeat biopsy or specialist pathology review? When should I expect any pending addendum?