title: Fluorescence in situ hybridization for detection of MAML2 rearrangements in oncocytic mucoepidermoid carcinomas: utility as a diagnostic test.
abstract: Oncocytic mucoepidermoid carcinoma poses diagnostic challenge because of its histologic overlap with other oncocytic salivary gland lesions, including Warthin tumor. Although the prognostic value of the t(11;19) MECT1-MAML2 fusion gene has been established in mucoepidermoid carcinoma, its diagnostic use in discriminating oncocytic mucoepidermoid carcinoma from histologic mimics is unexplored. We evaluated the translocation status in 14 cases of oncocytic mucoepidermoid carcinoma using a MAML2-11q21 break-apart probe spanning the entire chromosome region of the MAML2 gene and correlated these findings with clinicopathologic parameters including age, sex, stage, predominant growth pattern, grade, and p63 immunostaining pattern. All oncocytic mucoepidermoid carcinomas were parotid tumors with a mean patient age of 54.6 years (range, 9-85) and a female to male ratio of 5:2. Grade distribution was as follows: low grade, 9; intermediate grade, 2; and high grade, 3. The histologic patterns observed were as follows: solid, 4; cystic, 8 (of these, 5 had Warthin-like lymphoid stroma); and mixed, 2. Solid oncocytic mucoepidermoid carcinomas showed a diffuse p63 staining pattern, whereas cystic oncocytic mucoepidermoid carcinomas showed staining of the outer layer of intermediate cells ranging from a bilayer to areas of complex multilayering and plaque-like proliferation. Ten (71%) of the 14 cases showed a MAML2 rearrangement by fluorescence in situ hybridization. No correlation was seen between rearrangement status and histologic grade, growth pattern, or p63 staining pattern. However, we demonstrate that the presence of MAML2 rearrangement can be used as supportive evidence to distinguish oncocytic mucoepidermoid carcinoma from other oncocytic lesions.
authors.affiliation: Pathology and Laboratory Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA.
authors.forename: Joaquin J
authors.initials: JJ
authors.lastname: García
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Hunt
authors.forename: Ilan
authors.initials: I
authors.lastname: Weinreb
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: McHugh
authors.forename: E Leon
authors.initials: EL
authors.lastname: Barnes
authors.forename: Kathleen
authors.initials: K
authors.lastname: Cieply
authors.forename: Sanja
authors.initials: S
authors.lastname: Dacic
authors.forename: Raja R
authors.initials: RR
authors.lastname: Seethala
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018277:Carcinoma, Mucoepidermoid / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D002648:Child; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D005500:Follow-Up Studies; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000235:genetics / Q000473:pathology; D009367:Neoplasm Staging; D009687:Nuclear Proteins / Q000235:genetics*; D024862:Oxyphil Cells / Q000473:pathology; D010306:Parotid Gland / Q000473:pathology / Q000601:surgery; D010307:Parotid Neoplasms / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics*; D014178:Translocation, Genetic / Q000235:genetics; D016896:Treatment Outcome
chemical_list: C081876:CKAP4 protein, human; D004268:DNA-Binding Proteins; C471297:MAML2 protein, human; D008565:Membrane Proteins; D009687:Nuclear Proteins; D015534:Trans-Activators; D014157:Transcription Factors