Comprehensive Insights into CD20: Molecular Structure, Biological Functions, Therapeutic Applications, and Its Role in B-cell Malignancies

Abstract

Cluster of differentiation 20 (CD20), a membrane protein of the MS4A family, plays a key role in the proliferation, differentiation, and activation of B cells. In this review, we present an integrated analysis of the molecular structure of CD20. Its membrane domains, lipid raft localization, and critical phosphorylation sites are explored, followed by an investigation of the dynamic interactions of CD20 with membrane partners, including B cell receptors, MHC class II, CD40, and tetraspanins. CD20 oligomerization, supramolecular complex formation, and CD20 phosphorylation isoforms directly affect B-cell calcium signaling and functional responses. From a therapeutic perspective, specific anti-CD20 antibodies (e.g., rituximab) have shown clinical promise in B-cell malignancies, including chronic lymphocytic leukemia and non-Hodgkin lymphoma. However, emerging data suggest new mechanisms of therapeutic resistance to circulating CD20, requiring biomarker-guided dosing and novel therapeutic strategies. Here, advanced analytical techniques for CD20 detection, including ELISA, flow cytometry, and Western blotting, are presented in comprehensive detail. Current research on the diagnostic and prognostic significance of CD20 is also reviewed. Finally, structurefunction relationships, translational advances, and emerging challenges are analyzed, with a focus on basic immunology and the ongoing evolution of B-cell-targeted immunotherapies. CD20 plays a central role in B-cell signaling and remains an important therapeutic and diagnostic target in hematologic malignancies. Elucidating resistance mechanisms to anti-CD20 antibodies and developing more sensitive detection approaches are essential for improving clinical outcomes and supporting precision immunotherapy.