Examples of CD37 staining on human lymphoma samples. Sections from paraffin-embedded lymphoma tissue and xenograft tumors were stained with anti-CD37 antibody as described for Table 1 and staining intensity was scored as follows: 0 = negative; 1 = weak; 2 = moderate; and 3 = strong. Lymphoma samples representing each intensity level and sections from xenograft tumor models used in efficacy studies are shown. All images were acquired on an Olympus BX51 light microscope at ×40 magnification with an Olympus DP71 camera and DP Controller software (v3.2.1.276).