Prevalence of API2-MALT1 fusion gene in gastrointestinal mucosa-associated lymphoid tissue lymphomas and diffuse large B cell lymphomas

Abstract

To investigate the difference of the prevalence of t(11;18)(q21;q21)/API2-MALT1 fusion gene between gastrointestinal mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B cell lymphoma (DLBCL). A total of 57 cases gastrointestinal MALT lymphomas (38 gastric and 19 intestinal lymphomas), 32 DLBCL (28 gastric and 4 intestinal lymphomas) and 7 cases gastric DLBCL accompanied MALT lymphoma were collected from the Cancer Hospital of Fudan University. API2-MALT1 fusion gene was detected by fluorescent in situ hybridization (FISH) using both dual fusion translocation and break apart probes. Among gastrointestinal MALT lymphomas, API2-MALT1 fusion gene was found in 12 of 57 cases (21.1%, 10 gastric and 2 intestinal lymphomas). In contrast, the fusion gene was not found in all 32 DLBCL and 7 gastric DLBCL with MALT lymphoma component. There was statistical significant difference between two groups (chi(2) = 9.383, P = 0.001). API2-MALT1 fusion gene is a distinctive genetic aberration in MALT lymphomas, and is not present in DLBCL. The findings suggest that gastrointestinal tract MALT lymphomas with API2-MALT1 fusion gene may not transform into DLBCL, which may represent primary lymphoma or transformed API2-MALT1 negative MALT lymphomas.