Schematic illustration of the API2 and MALT1 gene structure and the position of primers used. (A) Known breakpoints are indicated by arrow-head, and nucleic acids are numbered according to cDNA sequence of the API2 (GenBank, NM_001165) and MALT1 genes (AF316597). The frequency of known breakpoints was shown. Arrows indicate the position of primers used. f-S and f-AS indicate sense and antisense primer for PCR from frozen tissue; p-S and p-AS, sense and antisense primer for PCR from paraffin-embedded tissues. BIR indicates baculovirus IAP repeat; CARD, caspase recruitment domain; DD, death domain; and Ig-L, Ig-like domain. (B) Distribution of breakpoints of the API2 and MALT1 genes in MALT lymphomas of different sites. GI indicates gastrointestine; L, lung; Con, conjunctiva; Orb, orbit; and SG, salivary gland.