What should you know about TTF-1 immunohistochemistry?

TTF-1 is a protein found in some normal cells, including cells associated with the lung and thyroid. In immunohistochemistry, an antibody is used to show whether the protein is present in the cells being examined and where the stain appears.

A detected or absent stain is one piece of the diagnostic puzzle. It can support a pathologist’s assessment of tumour origin, but it does not by itself identify the exact cancer type or determine treatment.

TTF-1 staining is commonly performed on tissue collected during a biopsy or surgery. Review the wording with the pathology team: note whether the result is positive or negative, the strength and distribution of staining, and which other markers were tested.

Your clinician may combine the result with imaging, the appearance of the cells and your medical history. If the sample is small or the pattern is unclear, further staining or molecular testing may be discussed before a final plan is made.

TTF-1 testing does not create physical symptoms because it is performed in the laboratory. After tissue collection, contact your team for increasing pain, redness, swelling, drainage or fever at the biopsy site. Obtain urgent care for heavy bleeding, fainting or severe breathing problems.

Ask what TTF-1 suggests about the tissue’s origin, which alternative diagnoses were considered, whether the sample is sufficient, and which additional markers or genomic tests could affect treatment choices. Ask for the complete pathology report if you do not already have it.