Primary pulmonary MALT lymphomas show frequent and heterogeneous cytogenetic abnormalities, including aneuploidy and translocations involving API2 and MALT1 and IGH and MALT1

Leukemia. 2004 Jan;18(1):156-60. doi: 10.1038/sj.leu.2403185.


API2-MALT1 fusion and aneuploidy are common chromosomal abnormalities in MALT lymphoma. In studying their incidence and relationship in primary pulmonary MALT lymphomas, a translocation involving MALT1 and IGH was also identified. In all, 28 primary pulmonary MALT lymphomas were studied by fluorescence in situ hybridization using an API2-MALT1 probe and multiple centromeric probes, as well as IGH-BCL2, IGH-MALT1, and MALT1 breakapart probes in selected cases. Seven (25%) had API2-MALT1 fusion; all seven lacked aneuploidy except for two with trisomy 3 in a small clone. Three (11%) had IGH-MALT1 fusion; two also showed trisomy 3 and 12. A total of 11 (39%) had aneuploidy only, with trisomy 3 and 18 being the most common. Ectopic nuclear bcl-10 expression, which has been previously associated with API2-MALT1, was seen by immunohistochemistry in 86% of API2-MALT1 fusion-positive cases, one IGH-MALT1 fusion-positive case, two aneuploidy-only cases, and two normal cases. In primary pulmonary MALT lymphomas, cytogenetic abnormalities are common (75%) and heterogeneous, encompassing API2-MALT1 and IGH-MALT1, which are mutually exclusive, as well as aneuploidy, which may be present in the latter but is rare in the former. Ectopic nuclear bcl-10 expression is associated with API2-MALT1 but may also be seen in IGH-MALT1 fusion-positive, aneuploidy-only, and normal cases.

MeSH terms

  • Adaptor Proteins, Signal Transducing*
  • Aneuploidy*
  • Apoptosis
  • B-Cell CLL-Lymphoma 10 Protein
  • Carrier Proteins / genetics
  • Caspases
  • Centromere / genetics
  • Chromosomes, Human, Pair 12
  • Chromosomes, Human, Pair 18
  • Chromosomes, Human, Pair 3
  • DNA Probes
  • Humans
  • Immunoglobulin Heavy Chains / genetics*
  • In Situ Hybridization, Fluorescence
  • Inhibitor of Apoptosis Proteins
  • Karyotyping
  • Lung Neoplasms / genetics
  • Lung Neoplasms / pathology
  • Lymphoma, B-Cell, Marginal Zone / genetics*
  • Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein
  • Neoplasm Proteins / genetics*
  • Proteins / genetics*
  • Translocation, Genetic*
  • Trisomy


  • Adaptor Proteins, Signal Transducing
  • B-Cell CLL-Lymphoma 10 Protein
  • BCL10 protein, human
  • Carrier Proteins
  • DNA Probes
  • Immunoglobulin Heavy Chains
  • Inhibitor of Apoptosis Proteins
  • Neoplasm Proteins
  • Proteins
  • Caspases
  • MALT1 protein, human
  • Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein