Distribution of BCL2 somatic mutations in FL and non-Hodgkin lymphoma subtypes. (A) Summary of somatic sequence mutations for BCL2 in FL and other non-Hodgkin lymphoma subtypes analyzed by Sanger sequencing in normal samples, a discovery (prevalence) cohort of 38 FLs, a validation cohort of 128 FLs collected exclusively at diagnosis, and cohorts of 117 post-FLs, 39 DLBCLs, 90 CLLs (50 with IGH rearrangement and 40 without), and 36 ALLs. (B) Schematic diagram of the BCL2 gene (top) and somatic mutation distribution along the BCL2 gene in the FL discovery cohort (n = 38), FL validation cohort (n = 128), and DLBCL cohort (n = 39). Exons 1, 2, and 3 are coded in green, purple, and red, respectively. Blue and red bars indicate synonymous and nonsynonymous mutations, respectively. (C-D) Sequencing chromatograms of representative mutated FL samples (lymph node) and paired normal (peripheral blood) DNA (C), or FL DNA and corresponding cDNA (D). Arrows point to the positions of nucleotide change, with the variant nucleotide labeled in red. (E) Overall frequency of BCL2 somatic mutations in FL and DLBCL. Within each group, samples without mutation are depicted in gray, samples with only synonymous mutations in blue, samples with mixed mutations in orange, and samples with nonsynonymous mutations in red.