CD20 is a cell surface-associated protein expressed during the middle to later stages of B cell maturation in the bone marrow, and on all normal mature B cells. CD20 ceases to be expressed at the terminal differentiation of B cells to plasma cells. CD20 is expressed on the great majority of mature B cell neoplasms, and on a significant subset of immature B cell neoplasms, but only rarely on plasmacytic neoplasms. CD20 is the target of the therapeutic antibody known as Rituxan.
Subcellular Localization: Membranous
Organ: Blood/Bone Marrow
CPT Code(s): 88342 or 88341 (reference only; CPTs may vary)
Turnaround Time: Within 1-2 business days of receipt
Schedule: Monday - Friday
• Formalin-fixed, paraffin-embedded (FFPE) tissue block or cell block - OR -
• 1 unstained slide for each test requested plus 3-4 additional unstained slides cut at 4µm