Translocations t(11;18)(q21;q21) and t(14;18)(q32;q21) are the main chromosomal abnormalities involving MLT/MALT1 in MALT lymphomas.
The recently discovered MLT/MALT1 gene is fused with the API2 gene in the t(11;18)(q21;q21), which characterizes about one-third of MALT lymphomas. In order to screen for variant translocations and amplifications of MLT/MALT1, we have developed a novel, undirected two-color interphase fluorescence in situ hybridization (FISH) assay with two PAC clones flanking MLT/MALT1. This assay was applied to 108 marginal zone B-cell lymphomas (MZBCLs), including 72 extranodal MALT lymphomas, 17 nodal, and 19 splenic MZBCL. In 19 MALT lymphomas (26%), but in none of the nodal or splenic MZBCL, separated hybridization signals of the MLT/MALT1 flanking probes, were found. Further FISH analyses showed that 12 of these 19 cases displayed the classical t(11;18) and the remaining seven cases revealed the novel t(14;18)(q32;q21), involving the MLT/MALT1 and IGH genes. The frequency at which these translocations occurred varied significantly with the primary location of disease. The t(11;18) was mainly detected in gastrointestinal MALT lymphomas, whereas the t(14;18) occurred in MALT lymphomas of the parotid gland and the conjunctiva. Amplification of MLT/MALT1 was not observed in any of the lymphomas analyzed. We conclude that the translocations t(11;18)(q21;q21) and t(14;18)(q21;q32) represent the main structural aberrations involving MLT/MALT1 in MALT lymphomas, whereas true amplifications of MLT/MALT1 occur rarely in MZBCL.
Murga Penas
E M
EM
Department of Medicine, Hamburg, Germany.
Hinz
K
K
Röser
K
K
Copie-Bergman
C
C
Wlodarska
I
I
Marynen
P
P
Hagemeijer
A
A
Gaulard
P
P
Löning
T
T
Hossfeld
D K
DK
Dierlamm
J
J
D001943:Breast Neoplasms / Q000473:pathology; D020169:Caspases; D002869:Chromosome Aberrations; D002874:Chromosome Mapping; D002880:Chromosomes, Human, Pair 11; D002883:Chromosomes, Human, Pair 14; D002887:Chromosomes, Human, Pair 18; D005770:Gastrointestinal Neoplasms / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics*; D000074884:Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein; D009363:Neoplasm Proteins / Q000235:genetics*; D010307:Parotid Neoplasms / Q000235:genetics; D011506:Proteins / Q000235:genetics*; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000235:genetics; D014178:Translocation, Genetic
D009363:Neoplasm Proteins; D011506:Proteins; D020169:Caspases; C400109:MALT1 protein, human; D000074884:Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein