The translocations t(6;18;11)(q24;q21;q21) and t(11;14;18)(q21;q32;q21) lead to a fusion of the API2 and MALT1 genes and occur in MALT lymphomas.

So far, only one variant translocation of the t(11;18)(q21;q21), the t(11;12;18) (q21;q13;q21), has been reported. We herein describe two new variant translocations, the t(6;18;11)(q24;q21;q21) and the t(11;14;18)(q21;q32;q21), occurring in mucosa-associated lymphoid tissue (MALT) lymphomas. In both cases, fluorescence in situ hybridization (FISH) and reverse transcriptase polymerase chain reaction (RT-PCR) revealed the presence of an 5'API2-3'MALT1 fusion product, encoded on the derivative chromosome 11. Exon 7 of API2 was fused with exon 5 of MALT1 in the t(11;14;18) and with exon 8 of MALT1 in the t(6;18;11). FISH revealed the involvement of the immunoglobulin locus in the t(11;14;18). Rapid amplification of cDNA ends (RACE)-PCR to detect the involved partner gene on 6q showed exclusively wild-type API2 and MALT1 sequences.