Neoplastic cells in mantle-cell lymphoma and Burkitt lymphoma coexpress BMI-1, EZH2, and Mib-1/Ki-67.

(A-B, first row) Double immunofluorescence of mantle cell lymphoma (MCL) shows BMI-1 and EZH2 with a majority of yellow (double-positive) tumor cells. The technique used is similar to that used in Figure 1with single red and single green colors (for clarity, only double-exposure overlay photographs are shown). Yellow cells are indicative of both green and red fluorescence. Note that bright red cells are BMI-1⁺ macrophages (MΦ). Three green cells (A, top) show distinct speckled yellow staining, whereas most other nuclei are evenly yellow (double-positive for BMI-1 and EZH2). (B) Double IF for EZH2 and Mib-1/Ki-67 (green and red, respectively) with most cells double-positive (yellow). Single green staining cells are referred to in the text. (C-D, second row) Double IF of Burkitt lymphoma (C) shows BMI-1 and EZH2 (red and green, respectively) with a majority of yellow (double-positive) tumor cells. (D) Double IF for Mib-1/Ki-67 and EZH2 (red and green, respectively) with most cells double-positive. Single-color controls in panels A to D are omitted. Photographs were taken from one representative experiment for each lymphoma (63× objective).