CD34

CD34 is a protein found on the surface of specific cells in your body, mainly stem cells (cells that can develop into various other types of cells), endothelial cells (blood vessel cells), and specific blood-forming cells. It plays an important role in cell growth and development, especially in forming new blood vessels and blood cells.

Why do pathologists test for CD34?

Pathologists test for CD34 to help identify and classify different types of tumours and blood-related conditions. Detecting CD34 helps determine whether certain types of stem cells, blood vessels, or blood-related cells are present in a tissue sample, aiding in accurate diagnosis.

How do pathologists test for CD34?

Pathologists test for CD34 using a method called immunohistochemistry. This involves applying antibodies designed to attach only to the CD34 protein on a thin tissue slice placed on a microscope slide. A chemical reaction then causes the cells containing CD34 to change colour. Cells showing this colour change are called “positive,” indicating they have CD34 on their surface, while cells without a colour change are called “negative.”

What types of normal cells and tissues will be positive for CD34?

Normal cells and tissues typically positive for CD34 include stem cells in bone marrow, endothelial cells lining blood vessels, and specific cells in the skin and soft tissues. These cells naturally express CD34 as part of their normal function.

What types of tumours will be positive for CD34?

Several types of tumours commonly test positive for CD34:

• Blood vessel tumours including hemangiomas and angiosarcomas.
• Gastrointestinal stromal tumour (GIST), a type of cancer found in the digestive tract.
• Dermatofibrosarcoma protuberans (DFSP), a type of skin cancer.
• Certain leukemias, cancers involving immature blood-forming cells.
• Solitary fibrous tumour, a type of tumour that can arise in various parts of the body.

Identifying CD34 in these tumours helps pathologists confirm the diagnosis and influences treatment decisions.

About this article

Doctors wrote this article to assist you in reading and comprehending your pathology report. Feel free to contact us with any questions about this article or your pathology report. To get a comprehensive introduction to your pathology report, read this article.