FOXP1 is a bone fide oncoprotein in DLBCL. (A-B) FoxP1 expression was analyzed by immunohistochemistry with the use of the tissue microarray described in Figure 3. Representative micrographs are shown (A); the fraction of MALT lymphoma and gDLBCL cases with high, low, and no FoxP1 expression is shown (B). The scale bar indicates 50μm. (C-D) FoxP1 expression as analyzed by immunohistochemistry of matched low-grade and high-grade lymphoma material from the same patients. Representative micrographs are shown for case 1 (C); scores on a scale of 0-3 are shown for all 3 cases (D). (E-H) Proliferation as determined by [³H] thymidine incorporation of U2932 (E), SUDHL4 (F), SUDHL6 (G), and SUDHL7 (H) cells 72 hours after electroporation with pre-miR34a, a FoxP1-specific siRNA or the respective negative control (NC) scrambled oligonucleotides. The FoxP1 staining in panels A through D was performed twice with similar results; the experiments shown in panels E through H were reproduced ≥ 3 and ≤ 5 times. Error bars indicate SD. Pictures were taken at room temperature with a Leica Leitz DM RB microscope (20×/0.5 NA) equipped with a Leica DFC 420C camera. Images were aquired using the Leica Application Suite 3.3.0 software.