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A cell surface protein expressed on mature B cells from mid-maturation through plasma cell development, including follicular dendritic cells. Positive in most B-cell lymphomas, some precursor B-ALL/lymphoblastic lymphomas, and lymphocyte predominant Hodgkin lymphomas. Target of Rituximab; CD20 expression may be lost in treated B-cell lymphomas.
Tissue Block: Formalin-fixed, paraffin-embedded (FFPE) tumor block preferred.
Unstained Slides: Recommended 2 charged slides per stain requested (minimum of 1 slide per stain), baked or unbaked.
Fixation: Tissue must be fixed in 10% neutral buffered formalin for 6–72 hours.
Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.