A20 Alterations in ARL. (A) Dual-color FISH analysis of tumor samples hybridized with A20 probe (green) and chromosome 6 centromeric probe (red). Top case shows wild-type A20. A20 heterozygous loss was shown in 5 cases (bottom left). One case was found to have A20 homozygous loss (bottom right). Magnification: Apochromatic 100× lens with 1.4 aperture; microscope: Nikon Eclipse 80i; camera: Jai CV-A10CL; software: Cytovision Imaging Software (Genetix Corp). (B) Representative chromatogram of normal DNA and tumor sample with A20 nonsense mutation in exon 2. This case had A20 monoallelic deletion, shown by FISH. The normal nucleotide peak in the mutated tumor sample probably represents infiltrating inflammatory cells. Software used was 4Peaks Version 1.7.2. (C) A20 Immunohistochemistry showing tumor cases with presence of A20 (left) and absence of A20 (right). Original magnification ×600 with 60×/0.80 objective lens. Microscope: Olympus BX 41; camera: Olympus Q-COLOR3; software: QCapture, Version 2.9.8.0 (Quantitative Imaging Corporation). (D) Incidence of A20 alteration is shown. (E) Incidence of A20 alteration in LMP-1 positive (+), negative (−), and intermediate (+/−) samples.