Clinical relevance of molecular diagnosis in childhood rhabdomyosarcoma.
Rhabdomyosarcoma may be divided into three subtypes--embryonal, alveolar, and undifferentiated sarcoma--which can be distinguished by molecular analysis. The authors applied reverse transcriptase-polymerase chain reaction analysis (RT-PCR) to analyze tumor samples from 14 children with rhabdomyosarcoma for the presence of the chimeric PAX3-FKHR transcript resulting from the translocation t(2;13)(q35,q14). Both fresh and paraffin-embedded tissues were used. In only nine specimens was the RNA intact for the analysis. The chimeric transcript was identified in seven samples: four alveolar type, one embryonal type, and two undifferentiated sarcoma. Histologic review was performed in the three samples with discordance between the molecular and histologic findings. A sample from a patient with a diagnosis of embryonal rhabdomyosarcoma on presentation and expression of PAX3-FKHR fusion transcript yielded a small focus of alveolar rhabdomyosarcoma and was reclassified as alveolar rhabdomyosarcoma. One of the samples from a patient with undifferentiated sarcoma was redefined as alveolar subtype; the diagnosis of the second undifferentiated sarcoma remained unchanged, in accordance with the histologic diagnosis. These findings further support the recommendation that molecular analysis be included in the diagnostic workup of childhood small round cell tumors to reach a more accurate diagnosis for tailoring of specific treatment.
Tobar
A
A
Department of Pathology, Beilinson Campus, Rabin Medical Center, Petah-Tiqva, Israel.
Avigad
S
S
Zoldan
M
M
Mor
C
C
Goshen
Y
Y
Zaizov
R
R
D000293:Adolescent; D000328:Adult; D019677:Artificial Gene Fusion; D002648:Child; D002675:Child, Preschool; D004273:DNA, Neoplasm / Q000032:analysis*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; D006801:Humans; D007223:Infant; D019656:Loss of Heterozygosity; D008297:Male; D009363:Neoplasm Proteins / Q000235:genetics*; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018232:Rhabdomyosarcoma, Alveolar / Q000175:diagnosis* / Q000235:genetics; D012983:Soft Tissue Neoplasms / Q000175:diagnosis* / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D016896:Treatment Outcome
D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; C085126:FOXO1 protein, human; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; D009363:Neoplasm Proteins; D000072041:PAX3 Transcription Factor; C489409:PAX3 protein, human; D051761:Paired Box Transcription Factors; D014157:Transcription Factors; C068686:Pax3 protein, mouse