LMP2-TR, but not LMP2A or LMP2B, are expressed in primary ENKTL tissue. (A) Immunohistochemistry of formalin-fixed, paraffin-embedded tissue sections with antibody clone 15F9, specific for LMP2A. Images were captured with a Nikon Coolpix E995 digital camera, via a Nikon Eclipse E400 microscope (optical magnification × 400). A case of EBV⁺ B cell PTLD is a positive control. Sections from 3 representative cases ENKTL (i-iii of 7) shown. (B) Quantitative RT-PCR data using cDNA derived from 7 primary ENKTL tissue biopsies and 1 EBV⁺ aggressive NK leukemia sample. QRT-PCR assays were performed to detect conventional LMP2A and LMP2B, LMP2-TR and transcripts containing exon 5-6 splice; the latter representing total LMP2 mRNAs. Ct₀ represents the assay threshold of detection. LMP2 transcript Ct values are normalized to cellular GAPDH Ct values. The left-hand y-axis represents Δ(Ct₀-Ct), while the right-hand axis shows the equivalent fold difference in transcript levels. Note: input cDNA was 2 μL in a reaction volume of 20 μL, compared with 5 μL in 25 μL for the cell line PCR studies for Figures 5 and 6.