Annexin I expression is undetectable in B-cell lymphomas. Panels A and B: CD 20 staining illustrates four localized clusters of B-cells (panel A). No Annexin I staining appears in the next serial section (panel B). Panels C and D: CD 20 positive B-cells appear in a defined cluster in this section (panel C). Staining for Annexin I clearly indicates absence of the protein in this B-cell cluster (panel D). However, Annexin I staining does localize in the epithelial layer of the section. Panels E and F: CD 20 positive B-cells form large follicles that are characteristic of this type of lymphoma (panel E). Annexin I staining does not localize in these follicles (panel F). Magnification: 40×.