IMMUNOHISTOCHEMISTRY, CDX-2

What this test checks

Detects CDX-2, a protein marker normally found in intestinal cells. Tumour cells that are CDX-2 positive suggest the cancer originated in or has features of the intestine/colon, helping to identify where a cancer started.

Why do people get this test?

When cancer has spread (metastasised) and the origin is unknown, CDX-2 helps trace it back to the bowel — crucial for choosing the right chemotherapy.

When you should consider this test

• When investigating cancer of unknown primary site
• When classifying gastrointestinal tumours
• When differentiating bowel cancer from other abdominal tumours

How to prepare

No preparation needed — performed on biopsy or surgical tissue.