engleski

Molecular detection of reciprocal translocation t(11 ; 22)(q24 ; q12) and follow-up in children with Ewing sarcoma and primitive neuroectodermal tumor

Objectives: The Ewing sarcoma (ES) family of tumor, appears as a bone or soft tissue lesion in a child and young adult. The most frequent translocation is EWS-FLI1 t(11q ; 22)(q24 ; q12) (90-95% cases), results in fusion of the EWS gene with a member of the ETS family. Our aim was to follow-up the patients with detected translocation in tumor tissue, peripheral blood and bone marrow. Patients and Methods: From October 2003 until January 2006 we received tumor samples (fixed in 10% buffered formalin and paraffin-embedded) paired with blood sdamples of eleven patients diagnosed with EWS during the treatment and we received six blood and bone marrow samples collected from patients after the treatment. Two patientzs died during chemotherapy. Total RNA was isolated from deparaffinized tissue sections by high pure RNA parrafin kit, from preserved blood samples by PAX gene Blood RNA Kit and from bone marrow samles by TRI reagent-BD extraction protocol. RNA quanlity check was performed by RT-PCR using specific primers for an interenal control-GAPDH (Glyceraldehyd-6-phosphate dehydrogenase). The EWS-FLI1 fusion transcripts were detected by RT-PCR using primers EWS22.2 Bam and FLI1C that specifically amplify both 125 pb type 1 fusion and 191 pb type 2 variant. Results: All samples were successfully amplified for GAPDH. Nine parafin samples were positive for type 1 EWS-FLI1 fusuin and two foe zype 2. Two blood samples were positive, one for type 1, and another one for type 2 fusion. The rest of the blood and bone marrow samples showed no positivity. Conclusion: This specific RT- PCR assay is essential for Ewing sarcoma diagnosis and monitoring minimal residual disease. All patients will be followed-up and impact of blood and bone marrow positivity will be assessed. Also the EWS/FLI1 type 1 and type 2 transcripts have to be consider as an important prognostical parameter.

Ewing sarcoma; translocation; molecular genetics

nije evidentirano