TRAF3 and LMP1 protein expression in human DLBCL samples. Formalin-fixed, paraffin-embedded tissue samples were stained for TRAF3 protein as described in “Methods.” (A) The top row shows representative samples identified by whole-exome sequencing as having decreased copy number for the TRAF3 gene stained for TRAF3 protein (brown); the bottom row shows representative samples identified as having a normal complement of TRAF3 genes stained for TRAF3 protein. (B) A control sample of normal human tonsil tissue stained for TRAF3 protein. (C) A sample with low/negative TRAF3 protein (previously determined by TRAF3 staining as in A) (left) stained in parallel for LMP1 (brown). An LMP1-negative specimen from the same tissue slide is shown on the right.