IMMUNOHISTOCHEMISTRY, TTF-1

What this test checks

Detects TTF-1 protein, which is expressed in lung adenocarcinoma and thyroid cancers. Helps confirm the origin of a tumour as lung or thyroid — particularly important when cancer has spread.

Why do people get this test?

TTF-1 is a key marker for classifying lung cancer subtype (adenocarcinoma vs. squamous) and for identifying thyroid cancer metastases. This guides the choice of targeted therapy and chemotherapy.

When you should consider this test

• When classifying lung cancer subtype
• When investigating a tumour of possible lung or thyroid origin
• When cancer has spread and the primary site is uncertain

How to prepare

No preparation needed — performed on biopsy or surgical tissue.