CD20 is a cell surface protein expressed on B cells and is a key target in B-cell malignancies, including:
- Non-Hodgkin’s Lymphoma (NHL) (e.g., diffuse large B-cell lymphoma, follicular lymphoma)
- Chronic Lymphocytic Leukemia (CLL)
- Burkitt’s Lymphoma
Why Target CD20 in Cancer?
- Highly expressed on malignant B cells but absent on stem cells and plasma cells, reducing off-target effects.
- Does not shed or internalize, making it ideal for antibody-based therapies.
Anti-CD20 Therapies in Cancer
- Rituximab (first anti-CD20 monoclonal antibody) – Used in NHL and CLL.
- Obinutuzumab (glycoengineered, more effective than rituximab in some lymphomas).
- Ofatumumab (targets a different CD20 epitope, used in CLL).
Mechanism of Action
- Direct cell killing (apoptosis).
- Antibody-Dependent Cellular Cytotoxicity (ADCC) – Immune cells attack CD20+ cancer cells.
- Complement-Dependent Cytotoxicity (CDC) – Activates complement system to destroy tumors.
Limitations
- Some tumors develop CD20-negative escape variants.
- Resistance can occur due to downregulation of CD20.
CD20 remains a cornerstone of B-cell cancer therapy, often combined with chemotherapy or newer immunotherapies (e.g., CAR-T cells).