Minimal residual disease (MRD) is the most powerful prognostic factor in pediatric acute lymphoblastic leukemia (ALL). Real-time quantitative polymerase chain reaction (RQ-PCR) represents the gold standard for molecular MRD assessment and risk-based stratification of front-line treatment. In the protocols of the Italian Association of Pediatric Hematology and Oncology (AIEOP) and the Berlin-Frankfurth-Munschen (BFM) group AIEOP-BFM ALL2009 and ALL2017, B-lineage ALL patients with high RQ-PCR-MRD at day+33 and positive at day+78 are defined slow early responders (SERs). Based on results of the AIEOP-BFM ALL2000 study, these patients are treated as high-risk also when positive MRD signal at day +78 is below the lower limit of quantification of RQ-PCR ("positive not-quantifiable," POS-NQ). To assess whether droplet digital polymerase chain reaction (ddPCR) could improve patients' risk definition, we analyzed MRD in 209 pediatric B-lineage ALL cases classified by RQ-PCR as POS-NQ and/or negative (NEG) at days +33 and/or +78 in the AIEOP-BFM ALL2000 trial. ddPCR MRD analysis was performed on 45 samples collected at day +78 from SER patients, who had RQ-PCR MRD ≥ 5.0 × 10-4 at day+33 and POS-NQ at day+78 and were treated as medium risk (MR). The analysis identified 13 of 45 positive quantifiable cases. Most relapses occurred in this patients' subgroup, while ddPCR NEG or ddPCR-POS-NQ patients had a significantly better outcome (P < 0.001). Overall, in 112 MR cases and 52 standard-risk patients, MRD negativity and POS-NQ were confirmed by the ddPCR analysis except for a minority of cases, for whom no differences in outcome were registered. These data indicate that ddPCR is more accurate than RQ-PCR in the measurement of MRD, particularly in late follow-up time points, and may thus allow improving patients' stratification in ALL protocols.

Droplet Digital PCR Improves IG-/TR-based MRD Risk Definition in Childhood B-cell Precursor Acute Lymphoblastic Leukemia / Della Starza, Irene; Nunes, Vittorio; Lovisa, Federica; Silvestri, Daniela; Cavalli, Marzia; Garofalo, Andrea; Campeggio, Mimma; De Novi, Lucia Anna; Soscia, Roberta; Oggioni, Carlotta; Mussolin, Lara; Biondi, Andrea; Guarini, Anna; Valsecchi, Maria Grazia; Conter, Valentino; Biffi, Alessandra; Basso, Giuseppe; Foà, Robin; Cazzaniga, Giovanni. - In: HEMASPHERE. - ISSN 2572-9241. - 5:3(2021), pp. 1-7. [10.1097/HS9.0000000000000543]

Droplet Digital PCR Improves IG-/TR-based MRD Risk Definition in Childhood B-cell Precursor Acute Lymphoblastic Leukemia

Della Starza, Irene;Nunes, Vittorio;Cavalli, Marzia;De Novi, Lucia Anna;Soscia, Roberta;Guarini, Anna;Foà, Robin;
2021

Abstract

Minimal residual disease (MRD) is the most powerful prognostic factor in pediatric acute lymphoblastic leukemia (ALL). Real-time quantitative polymerase chain reaction (RQ-PCR) represents the gold standard for molecular MRD assessment and risk-based stratification of front-line treatment. In the protocols of the Italian Association of Pediatric Hematology and Oncology (AIEOP) and the Berlin-Frankfurth-Munschen (BFM) group AIEOP-BFM ALL2009 and ALL2017, B-lineage ALL patients with high RQ-PCR-MRD at day+33 and positive at day+78 are defined slow early responders (SERs). Based on results of the AIEOP-BFM ALL2000 study, these patients are treated as high-risk also when positive MRD signal at day +78 is below the lower limit of quantification of RQ-PCR ("positive not-quantifiable," POS-NQ). To assess whether droplet digital polymerase chain reaction (ddPCR) could improve patients' risk definition, we analyzed MRD in 209 pediatric B-lineage ALL cases classified by RQ-PCR as POS-NQ and/or negative (NEG) at days +33 and/or +78 in the AIEOP-BFM ALL2000 trial. ddPCR MRD analysis was performed on 45 samples collected at day +78 from SER patients, who had RQ-PCR MRD ≥ 5.0 × 10-4 at day+33 and POS-NQ at day+78 and were treated as medium risk (MR). The analysis identified 13 of 45 positive quantifiable cases. Most relapses occurred in this patients' subgroup, while ddPCR NEG or ddPCR-POS-NQ patients had a significantly better outcome (P < 0.001). Overall, in 112 MR cases and 52 standard-risk patients, MRD negativity and POS-NQ were confirmed by the ddPCR analysis except for a minority of cases, for whom no differences in outcome were registered. These data indicate that ddPCR is more accurate than RQ-PCR in the measurement of MRD, particularly in late follow-up time points, and may thus allow improving patients' stratification in ALL protocols.
2021
minimal residual disease; pediatric acute lymphoblastic leukemia; droplet digital pcr
01 Pubblicazione su rivista::01a Articolo in rivista
Droplet Digital PCR Improves IG-/TR-based MRD Risk Definition in Childhood B-cell Precursor Acute Lymphoblastic Leukemia / Della Starza, Irene; Nunes, Vittorio; Lovisa, Federica; Silvestri, Daniela; Cavalli, Marzia; Garofalo, Andrea; Campeggio, Mimma; De Novi, Lucia Anna; Soscia, Roberta; Oggioni, Carlotta; Mussolin, Lara; Biondi, Andrea; Guarini, Anna; Valsecchi, Maria Grazia; Conter, Valentino; Biffi, Alessandra; Basso, Giuseppe; Foà, Robin; Cazzaniga, Giovanni. - In: HEMASPHERE. - ISSN 2572-9241. - 5:3(2021), pp. 1-7. [10.1097/HS9.0000000000000543]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1646334
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