MyPathologyReport
April 3, 2023
CD20 is a protein primarily expressed on the surface of B cells, a type of white blood cell that plays a key role in the immune system’s defense against infections. This protein is expressed throughout the entire B cell development process, from pre-B cells to mature B cells, but is not present on plasma cells, which are the cells that make antibodies. It is involved in the regulation of B cell activation, differentiation, and proliferation. Other B cell markers include CD19, CD79, and PAX-5.
Two common tests used to look for CD20 in a tissue sample are immunohistochemistry and flow cytometry. Immunohistochemistry is performed on a tissue sample attached to a glass slide. The slide is then examined under the microscope. Flow cytometry uses a special machine to count and analyze the number of cells in a tissue sample that are making this protein.
Can normal cells be positive for CD20?
Yes. Normal, healthy B cells are positive for CD20. These cells are found throughout the body.
CD20 positive cancers
Most lymphomas that start from B cells will be positive for CD20.
CD20-positive lymphomas include:
- Chronic lymphocytic leukemia (CLL)
- Small lymphocytic lymphoma (SLL)
- Follicular lymphoma
- Diffuse large B cell lymphoma
- Mantle cell lymphoma
About this article
Doctors wrote this article to assist you in reading and comprehending your pathology report. Feel free to reach out to us with any questions about this article or your pathology report. To get a comprehensive introduction to your pathology report, read this article.
Other helpful resources
Atlas of pathology
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