[Significance of molecular-cytogenetic findings in mucoepidermoid carcinoma as an example of salivary gland tumors].
Chromosome translocations in tumors frequently give rise to fusion genes encoding proteins with oncogenic activities. Mucoepidermoid carcinomas (MEC) are characterized by a t(11;19)(q21-22;p13) translocation found in approximately 60% of the tumors. This t(11;19) translocation results in a fusion gene consisting of exon 1 of the MECT 1 gene and exons 2-5 of the MAML 2 gene. As a result of the t(11;19) a fusion protein is generated which, independent of NOTCH-ligands, activates the transcription of the NOTCH target gene HES 1. The altered function of MAML 2 causes a disruption of NOTCH signalling which suggests a novel mechanism of tumorigenesis. Pending the elucidation of the t(11;19) at the molecular level of an apparently identical chromosomal translocation in Warthin's tumor, the identification of the translocation in MEC by FISH- and/or RT-PCR-analyses may become important in diagnosis and might have prognostic relevance. Warthin's tumors are benign salivary gland neoplasms with a distinctive histomorphology and histogenesis completely different from MEC.
Röser
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Speicheldrüsenregister, Institut für Oralpathologie, Universitätsklinikum Hamburg-Eppendorf.
Jäkel
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Bullerdiek
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Löning
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D018277:Carcinoma, Mucoepidermoid / Q000145:classification / Q000235:genetics* / Q000473:pathology*; D002869:Chromosome Aberrations; D005091:Exons; D006801:Humans; D015514:Oncogene Proteins, Fusion / Q000032:analysis / Q000235:genetics; D016133:Polymerase Chain Reaction; D012468:Salivary Gland Neoplasms / Q000235:genetics* / Q000473:pathology; D014178:Translocation, Genetic
C495418:MECT1-MAML2 fusion protein, human; D015514:Oncogene Proteins, Fusion