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Immunohistochemistry markers in lymphoma, explained for families | CION Cancer Clinics
CD20 and CD3 are the first markers most lymphoma reports list. CD20 positive usually points to a lymphoma that began in B cells; CD3 positive in the abnormal cells points to T cells. Other stains such as CD30, CD10 and cyclin D1 then narrow down the exact subtype. This page explains what the markers mean, why CD20 matters for treatment, and what the report cannot tell you. At CION Cancer Clinics, our haematology team plans myeloma and lymphoma care with you, discussed at a tumour board and explained in plain words.
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Medically reviewed by Dr. Basudev PokhrelConsultant Haematologist · last reviewed September 2026, next review due September 2027
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On this page
- What do CD20 and CD3 on my biopsy report mean?
- Which groups of markers will I see on the report?
- What do the common markers mean in plain words?
- What happens to the biopsy before the markers are reported?
- Why does CD20 matter when treatment is planned?
- What do families often get wrong about marker reports?
- What can the marker report not tell you?
- Common questions about lymphoma marker reports
The short answer
What do CD20 and CD3 on my biopsy report mean?
CD20 and CD3 are labels that sit on the surface of immune cells. CD20 positive usually means the lymphoma started in B cells, and CD3 positive usually means it started in T cells. That single difference shapes the name of the lymphoma and the treatment your haematologist plans.
What immunohistochemistry actually is
Immunohistochemistry, shortened to IHC on your report, is a staining test done on the biopsy tissue. The laboratory adds antibodies that stick only to one marker. Where the marker is present, the cells turn brown under the microscope. The pathologist, the doctor who reads tissue, then records each marker as positive or negative.
Why one marker is never enough
No single stain names a lymphoma. The pathologist reads a panel of markers together, alongside the shape of the cells and how they are arranged. A report that says "CD20 positive" is the start of the answer, not the whole of it. Most reports list eight to fifteen markers before giving a final diagnosis.
The final diagnosis line at the bottom of the report matters more than any single marker above it. Read that line first.Reading the panel
Which groups of markers will I see on the report?
The markers fall into a few families. Each family answers a different question about the cells.
Which cell family?
These markers tell B cells from T cells. They come first because every later decision depends on them.
Common markers
- CD20, CD19, PAX5, CD79a for B cells
- CD3, CD5, CD4, CD8 for T cells
Hodgkin or non-Hodgkin?
Hodgkin lymphoma has large, unusual cells that carry a distinct pattern. They are usually positive for CD30 and CD15 and weak or negative for CD20.
CD30 is also seen in some T-cell lymphomas, so it is read with the rest of the panel.Which subtype?
Once the family is known, other markers narrow the name down. This is how follicular, mantle cell and diffuse large B-cell lymphoma are told apart.
Common markers
- CD10, BCL6, MUM1
- BCL2, cyclin D1, CD23
- ALK in some T-cell lymphomas
How fast is it growing?
Ki-67 shows what share of cells are dividing. It adds to the picture of how active the lymphoma is, but it is not a stage and not a prognosis on its own.
Not sure whether this applies to you?
Ask an oncologistOn your report
What do the common markers mean in plain words?
- CD20
- A marker on most B cells. It also matters for treatment, because some antibody medicines are aimed at it.
- CD3
- The main marker for T cells. Strong CD3 staining in the abnormal cells points to a T-cell lymphoma.
- CD30 and CD15
- Markers that, read together, often point to Hodgkin lymphoma.
- CD10, BCL6 and MUM1
- Used in diffuse large B-cell lymphoma to suggest whether the cells look like germinal centre cells or activated cells.
- Cyclin D1
- Usually positive in mantle cell lymphoma, and helps separate it from look-alike lymphomas.
- Focal or weak positive
- Only some cells, or only faintly, took up the stain. Ask what that means in your specific report.
Behind the report
What happens to the biopsy before the markers are reported?
The tissue is fixed and set in wax
The lymph node or tissue piece is preserved and set into a small wax block. Thin slices are cut from this block. The same block can be used again later for more stains, so keep a record of where it is stored.
A first look under the microscope
The pathologist studies the basic stain first. The pattern of the cells decides which marker panel is worth running, so the panel is chosen for your tissue rather than taken from a fixed list.
Markers are added in rounds
A first set of stains answers B cell or T cell. A second set often follows to settle the subtype. This is why some reports take longer than others, and why a report may say "further stains to follow".
The final report is signed
The pathologist brings the shape of the cells and every marker together into one diagnosis. Extra tests such as FISH, which looks for gene changes, may be added for some subtypes.
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From report to plan
Why does CD20 matter when treatment is planned?
CD20 is one of the few markers that points straight at a medicine. When a B-cell lymphoma is CD20 positive, the plan often includes an antibody medicine such as rituximab, which attaches to CD20 and helps the immune system remove those cells. Your haematologist decides whether it fits, how it is given and for how long.
Who this does not apply to
A CD20 antibody does not help lymphomas that lack CD20. Most T-cell lymphomas are CD20 negative, and classical Hodgkin lymphoma usually is too. For those, the plan is built on other markers, such as CD30, and on the stage and your general health.
When the marker changes over time
A lymphoma that comes back after treatment can sometimes lose CD20. This is one reason a fresh biopsy is often advised at relapse rather than relying on the first report. The first report describes the lymphoma as it was then, not necessarily as it is now.
Commonly believed
What do families often get wrong about marker reports?
"More positive markers means a worse cancer."
Positive and negative here do not mean good and bad. They describe what the cells carry, so the lymphoma can be named. A long list of positives is simply a detailed description.
"CD3 positive means it is a T-cell lymphoma."
Almost every lymph node contains normal T cells, and they stain for CD3 too. What matters is whether the abnormal cells carry it. The pathologist's summary makes that distinction for you.
"The markers are done, so no more tissue is ever needed."
If the panel cannot settle the subtype, or the sample is very small, a larger biopsy may be requested. A small needle sample sometimes cannot show how the cells are arranged, and that pattern counts as much as the stains.
"A second opinion means repeating the biopsy."
Usually it does not. The existing wax block and slides can be sent to another pathologist for review, and extra stains can be run on the same block.
Being straight with you
What can the marker report not tell you?
The IHC report names the lymphoma. It does not tell you the stage, which is how far it has spread, and it does not tell you how you will respond to treatment. Staging needs scans and sometimes a bone marrow test. The outlook depends on the subtype, the stage, blood tests such as LDH and your overall health, read together.
When the report is unclear
Some reports end with words such as "suggestive of" or "favour". That means the pathologist is leaning towards a diagnosis but wants more evidence. Ask whether extra stains, a review by a lymphoma pathologist or a larger biopsy is planned. Do not start treatment on a report that is still uncertain.
What to bring to your appointment
Bring the full report, not only the last page, and the name of the laboratory that holds the block. At CION, the haematology team reads the report with your scans and discusses the case at a tumour board, where several specialists agree the plan together.
This page explains the terms. It cannot interpret your own report. Your haematologist can.Questions we are asked
Common questions about lymphoma marker reports
My report says CD20 positive. Is that good or bad?
It is neither good nor bad on its own. It tells your doctors the lymphoma comes from B cells, and it opens the option of medicines aimed at CD20. Whether you are offered one depends on the full diagnosis, the stage and your health, which your haematologist will explain at the appointment.
Both CD20 and CD3 are positive. Is that a mistake?
Usually not. A lymph node holds both B cells and T cells, so both markers often appear. The report should say which cells are the abnormal ones. If it is not clear, ask the pathologist or your haematologist to explain which marker the lymphoma cells carry.
How long does an IHC report take?
It varies by laboratory and by how many rounds of stains are needed. A simple case can be quicker. A case that needs a second panel or gene tests takes longer. Ask the laboratory for an expected date, and tell your haematologist if the wait stretches on without news.
What is the difference between IHC and flow cytometry?
Both look for the same kinds of markers. IHC stains a slice of fixed tissue, so the pathologist sees where the cells sit. Flow cytometry tests cells in fluid, such as blood or marrow, and counts them by machine. Some cases use both, because each shows something the other misses.
Can I get my slides reviewed somewhere else?
Yes. Ask the laboratory that did the biopsy to release the wax block and slides with the report. Another pathologist can then review them and add stains if needed. This is common in lymphoma, because the subtype decides treatment and some subtypes are hard to tell apart.
Does Ki-67 on the report tell me the stage?
No. Ki-67 shows how many cells were dividing in the sample, which hints at how fast the lymphoma grows. Stage describes how far it has spread in the body. The two are separate, and stage comes from scans and sometimes a marrow test rather than the biopsy stains.
Why was a second biopsy asked for after the markers?
Usually because the first sample was too small or the markers did not settle the subtype. A whole lymph node or a larger core shows how the cells are arranged, which a thin needle sample cannot. It is a request for clarity, and it does not mean the lymphoma is worse.
Who should explain the report to us?
A haematologist or medical oncologist who treats lymphoma, with the full report and your scans in front of them. Reading markers online without the rest of the picture often causes needless fear. Write your questions down and bring the family member who will help with decisions.
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Sources
- National Cancer Institute — Adult Non-Hodgkin Lymphoma Treatment (PDQ)
- National Cancer Institute — Pathology Reports
- American Cancer Society — Non-Hodgkin Lymphoma
- Cancer Research UK — Non-Hodgkin lymphoma
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
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