Absence of EWS/FLI1 fusion in olfactory neuroblastomas indicates these tumors do not belong to the Ewing's sarcoma family.
The balanced reciprocal translocation t(11;22)(q24;q12) is a specific molecular marker for the Ewing's sarcoma family of tumors (ESFT). Based on the detection of this translocation in some olfactory neuroblastomas (ONBs), it has been proposed that ONBs also belong to the ESFT. Others have challenged this hypothesis; however, the rarity of ONBs, as well as the lack of molecular techniques that work reliably on formalin fixed tissue, have precluded the molecular analysis of a significant number of cases. We evaluated the immunophenotypic and molecular features of 17 paranasal small round neuroectodermal tumors using routinely fixed tissue. Probes localizing to 22q12 (EWS) and 11q24 (FLI-1) were used in a standard 2-color fluorescence in situ hybridization (FISH) assay to evaluate EWS/FLI1 fusion on the der(22). Sixteen tumors were mic-2 negative, whereas 1 tumor was mic-2 positive, compatible with ONB and ESFT, respectively. Thirteen of 15 ONBs could be evaluated by FISH, and all 13 were negative for the EWS/FLI1 fusion. Distinct fusion signals were identified in the single paranasal ESFT. Our findings indicate that ONBs lack the EWS/FLI1 fusion and are unrelated to the ESFT; however, true ESFTs may rarely occur as primary sinonasal tumors.
Kumar
S
S
Laboratory of Pathology, National Cancer Institute, and Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-1500, USA.
Perlman
E
E
Pack
S
S
Davis
M
M
Zhang
H
H
Meltzer
P
P
Tsokos
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D018304:Esthesioneuroblastoma, Olfactory / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity; D009669:Nose Neoplasms / Q000378:metabolism*; D015514:Oncogene Proteins, Fusion / Q000378:metabolism*; D051789:Proto-Oncogene Protein c-fli-1; D034802:RNA-Binding Protein EWS; D014157:Transcription Factors / Q000378:metabolism*
C106031:EWS-FLI fusion protein; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D034802:RNA-Binding Protein EWS; D014157:Transcription Factors