Using this rapid and simple method, we could detect API2-MALT1 fusion transcripts in 5 of 15 (33%) archival cases of MALT lymphoma for a frequency comparable with those of RT-PCR assays using frozen materials.     ///    API2-MALT1 fusion transcripts involved in mucosa-associated lymphoid tissue lymphoma: multiplex RT-PCR detection using formalin-fixed paraffin-embedded specimens..     ///    The lung was the preferential anatomical site of origin of MALT lymphomas harboring API2-MALT1 fusion.     ///    "Our multiplex RT-PCR assay, which can be used for routinely-processed paraffin samples, should serve as a useful molecular tool for clarifying the clinicopathological significance of API2-MALT1 fusion in MALT lymphoma.. "