TY - JOUR
T1 - Precision diagnostics of Ewing’s sarcoma by liquid biopsy
T2 - circulating EWS-FLI1 fusion transcripts
AU - Allegretti, Matteo
AU - Casini, Beatrice
AU - Mandoj, Chiara
AU - Benini, Stefania
AU - Alberti, Laurent
AU - Novello, Mariangela
AU - Melucci, Elisa
AU - Conti, Laura
AU - Covello, Renato
AU - Pescarmona, Edoardo
AU - Milano, Giuseppe Maria
AU - Annovazzi, Alessio
AU - Anelli, Vincenzo
AU - Ferraresi, Virginia
AU - Biagini, Roberto
AU - Giacomini, Patrizio
PY - 2018/1/1
Y1 - 2018/1/1
N2 - Background: Limited information is available on the applicative value of liquid biopsy (LB) in rare tumors, including Ewing’s sarcoma (ES). The accepted precision diagnostics standards would greatly benefit from a non-invasive LB test monitoring pathognomonic gene rearrangements in the bloodstream. Methods: Tissue and blood samples were collected from six and four ES patients, respectively. Plasma was cleared by two successive rounds of centrifugation and stored frozen until RNA extraction by the QIAmp CNA kit. RNA was retro-transcribed and subjected to real-time quantitative polymerase chain reaction (RT-qPCR) and digital polymerase chain reaction (dPCR). Reactions were set up using two custom primer sets identifying types 1 and 2 EWS-FLI1 fusion transcripts. Results: The two prevalent types of EWS-FLI1 rearrangements could be identified using only two sets of polymerase chain reaction primers, regardless of patient-specific EWS-FLI1 DNA breakpoints. RT-qPCR and dPCR discriminated the two variants in five tumor tissue RNAs and in four circulating tumor RNAs (ctRNAs). Of note, EWS-FLI1 molecular diagnosis was possible using blood samples even when tumor tissue was not available. ctRNA levels correlated (p < 0.05) with volume-based positron emission tomography (PET) parameters (metabolic tumor volume and total lesion glycolysis), and allowed the fine tracking of disease course after surgery, during adjuvant as well as neoadjuvant chemotherapy, and at follow up in one patient. Conclusions: To our knowledge, this is one of the few single-marker LB assays in solid tumors specifically designed to detect rearranged RNAs in blood, and the first study describing EWS circulating tumor RNAs in ES patients. Altogether, our results support the idea that LB may have a considerable impact on ES patient monitoring and management.
AB - Background: Limited information is available on the applicative value of liquid biopsy (LB) in rare tumors, including Ewing’s sarcoma (ES). The accepted precision diagnostics standards would greatly benefit from a non-invasive LB test monitoring pathognomonic gene rearrangements in the bloodstream. Methods: Tissue and blood samples were collected from six and four ES patients, respectively. Plasma was cleared by two successive rounds of centrifugation and stored frozen until RNA extraction by the QIAmp CNA kit. RNA was retro-transcribed and subjected to real-time quantitative polymerase chain reaction (RT-qPCR) and digital polymerase chain reaction (dPCR). Reactions were set up using two custom primer sets identifying types 1 and 2 EWS-FLI1 fusion transcripts. Results: The two prevalent types of EWS-FLI1 rearrangements could be identified using only two sets of polymerase chain reaction primers, regardless of patient-specific EWS-FLI1 DNA breakpoints. RT-qPCR and dPCR discriminated the two variants in five tumor tissue RNAs and in four circulating tumor RNAs (ctRNAs). Of note, EWS-FLI1 molecular diagnosis was possible using blood samples even when tumor tissue was not available. ctRNA levels correlated (p < 0.05) with volume-based positron emission tomography (PET) parameters (metabolic tumor volume and total lesion glycolysis), and allowed the fine tracking of disease course after surgery, during adjuvant as well as neoadjuvant chemotherapy, and at follow up in one patient. Conclusions: To our knowledge, this is one of the few single-marker LB assays in solid tumors specifically designed to detect rearranged RNAs in blood, and the first study describing EWS circulating tumor RNAs in ES patients. Altogether, our results support the idea that LB may have a considerable impact on ES patient monitoring and management.
KW - circulating tumor RNA
KW - Ewing’s sarcoma
KW - EWS-FL1 gene rearrangements
KW - liquid biopsy
KW - PET imaging
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U2 - 10.1177/1758835918774337
DO - 10.1177/1758835918774337
M3 - Article
AN - SCOPUS:85054041117
VL - 10
JO - Therapeutic Advances in Medical Oncology
JF - Therapeutic Advances in Medical Oncology
SN - 1758-8340
ER -