title: Fluorescence in-situ hybridization identifies Mastermind-like 2 (MAML2) rearrangement in odontogenic cysts with mucous prosoplasia: a pilot study.
abstract: OBJECTIVE
  The pathogenesis of intraosseous mucoepidermoid carcinoma (IMEC) remains unknown. Coexistence with odontogenic cysts (ODC) has been reported in 32-48% of IMEC. Furthermore, prosoplastic mucous cells are often seen in the epithelial lining of ODCs. MECT1-MAML2 fusion transcripts have been identified in >66% of salivary gland MEC cases. The aim of this study was to investigate the presence of MAML2 rearrangement in ODCs featuring mucous prosoplasia.
  
  
  RESULTS
  Ten cases of ODC with a mucous cell component and three cases of IMEC were evaluated using fluorescence in-situ hybridization. All cases occurred in the mandible. The ODCs exhibited a M:F ratio of 4:1 (mean age 49.2 years), while all IMECs occurred in women (mean age 68.3 years). All three IMECs demonstrated MAML2 rearrangement, in 26-61% of tumour cells. Successful hybridization was observed in nine of 10 cases of ODC. In two of these nine, there was MAML2 rearrangement in 12% and 24% of the lining epithelial cells, while three of the nine showed rearrangement in 7-8% of cells; the remaining four cases were negative.
  
  
  CONCLUSIONS
  We identified MAML2 rearrangements in five of nine ODCs lined by mucus-secreting cells. This suggests that at least a subset of ODCs with mucous prosoplasia are characterized by molecular events considered diagnostic for intraosseous and extraosseous MEC.
authors.affiliation: Division of Oral and Maxillofacial Pathology, School of Dentistry, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Prokopios P
authors.initials: PP
authors.lastname: Argyris
authors.forename: Rebecca N
authors.initials: RN
authors.lastname: Wehrs
authors.forename: Joaquín J
authors.initials: JJ
authors.lastname: García
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Koutlas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018277:Carcinoma, Mucoepidermoid / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008339:Mandibular Neoplasms / Q000235:genetics*; D008875:Middle Aged; D009687:Nuclear Proteins / Q000235:genetics*; D009807:Odontogenic Cysts / Q000235:genetics* / Q000473:pathology*; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D010865:Pilot Projects; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics*; D055815:Young Adult
chemical_list: D004268:DNA-Binding Proteins; C471297:MAML2 protein, human; D009687:Nuclear Proteins; D015514:Oncogene Proteins, Fusion; D015534:Trans-Activators; D014157:Transcription Factors
keywords: FISH; MAML2 rearrangement; mucoepidermoid carcinoma; mucous prosoplasia; odontogenic cyst