title: EWSR1 rearrangement is a frequent event in papillary thyroid carcinoma and in carcinoma of the thyroid with Ewing family tumor elements (CEFTE).
abstract: Carcinomas of the thyroid with Ewing family tumor element (CEFTEs) are small-cell thyroid tumors with epithelial differentiation that disclose p63 expression and EWSR1-FLI1 rearrangement, carry a favorable prognosis and may co-exist with papillary thyroid carcinoma (PTC) foci. Two histogenetic hypotheses have been advanced regarding the origin of CEFTEs: arising in PTCs or in solid cell nests (SCN). A total of 3 CEFTEs, 54 PTCs, and 10 SCNs were reviewed, and fluorescence in situ hybridization (FISH) technique was performed in all cases to search for the presence of EWSR1 rearrangements. The three CEFTEs disclosed the EWSR1-FLI1 rearrangement both in the small cell and in the PTC component. Out of the 54 PTC cases, 28 (51.9%) were positive, 20 (37.0%) were negative, and 6 (11.1%) were inconclusive for EWSR1 rearrangement; in two of the positive PTC cases, the EWSR1-FLI1 rearrangement was detected. Classic PTC disclosed more often the EWSR1 rearrangement than other PTC variants (p = 0.031). PTCs with EWSR1 rearrangement disclosed a lower percentage of nuclei with EWSR1 polysomy than those without EWSR1 rearrangement (p = 0.001). Out of the 10 SCNs, 7 (70.0%) were negative and 3 (30.0%) were inconclusive for the EWSR1 rearrangement. Monosomic nuclei were more frequent (mean of 44.3%) in SCNs than in PTCs (p < 0.001). The presence of the EWSR1-FLI1 rearrangement in PTC component of all studied CEFTEs and the existence of the EWSR1 rearrangement in some PTCs favor the origin of CEFTE from PTC. The high frequency of EWSR1 rearrangements in PTC may represent a new diagnostic marker of these tumors.
authors.affiliation: Ipatimup Diagnostics, Institute of Molecular Pathology and Immunology of Porto University, R. Júlio Amaral de Carvalho, 45, Ipatimup, 4200-135, Porto, Portugal.|Institute of Biomedical Science Abel Salazar-ICBAS, University of Porto, Porto, Portugal.
authors.forename: G
authors.initials: G
authors.lastname: Oliveira
authors.affiliation: Ipatimup Diagnostics, Institute of Molecular Pathology and Immunology of Porto University, R. Júlio Amaral de Carvalho, 45, Ipatimup, 4200-135, Porto, Portugal.|Medical Faculty, University of Porto, Porto, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Polónia
authors.affiliation: Department of Anatomic Pathology, Clinical University Hospital, Servicio Gallego de Salud (SERGAS), University of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Cameselle-Teijeiro
authors.affiliation: Ipatimup Diagnostics, Institute of Molecular Pathology and Immunology of Porto University, R. Júlio Amaral de Carvalho, 45, Ipatimup, 4200-135, Porto, Portugal.|Medical Faculty, University of Porto, Porto, Portugal.
authors.forename: D
authors.initials: D
authors.lastname: Leitão
authors.affiliation: Pathology Department, Vinalopó Hospital, Elche, Spain.|Pathology Department, Örebro University Hospital, Örebro, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Sapia
authors.affiliation: Ipatimup Diagnostics, Institute of Molecular Pathology and Immunology of Porto University, R. Júlio Amaral de Carvalho, 45, Ipatimup, 4200-135, Porto, Portugal.|Medical Faculty, University of Porto, Porto, Portugal.|Anatomic Pathology Service, Centro Hospitalar de São João, Porto, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Sobrinho-Simões
authors.affiliation: Ipatimup Diagnostics, Institute of Molecular Pathology and Immunology of Porto University, R. Júlio Amaral de Carvalho, 45, Ipatimup, 4200-135, Porto, Portugal. celoy@ipatimup.pt.|Medical Faculty, University of Porto, Porto, Portugal. celoy@ipatimup.pt.
authors.forename: C
authors.initials: C
authors.lastname: Eloy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology*; D002291:Carcinoma, Papillary; D002648:Child; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000473:pathology*; D055815:Young Adult
chemical_list: C576197:EWSR1-FLI1 fusion protein, human; D015514:Oncogene Proteins, Fusion
keywords: EWSR1 rearrangement; EWSR1-FLI1; Ewing sarcoma; Papillary thyroid carcinoma; Small cell carcinoma