Table. 1.

Table. 1.

Characteristics of classical minimal residual disease assays used in pediatric acute lymphoblastic leukemia

Assay technique and targets Applicability and sensitivity Advantages Disadvantages
Multiparameter flow cytometry for LAIPs >90% Wide applicability Lower sensitivity than RQ-PCR
3-4 colors: 10−3-10−4 Low cost Requires fresh samples (<24 h old)
Short turnaround time Requires diagnostic sample to identify LAIPs
6-8 colors: 10−4-10−5 Exclusion of apoptotic cells lacking leukemogenic potential Immunophenotypic shifts may cause false negatives
Requires high level of expertise to interpret data
Analysis at cell population or single cell level Limited standardization
Real-time quantitative PCR for fusion transcripts (mainly on RNA) B-ALL: 25-30% High sensitivity Limited applicability
Short turnaround time RNA instability
T-ALL: 15-25% Stable target throughout treatment Risk of contamination
Wide availability of primer sets Requires standard curves
10−4-105 Standardization for recurrent fusion transcripts Risk of inaccurate quantitation
False positive results owing to nonspecific amplification of normal DNA or of cells without leukemogenic potential
Real-time quantitative PCR for IG/TCR gene rearrangements 90-95% High sensitivity Long turnaround time
10−4-105 Wide applicability Generation of patient-specific allele specific oligonucleotide primer sets is cumbersome
Standardized protocol and data interpretation Requires prior knowledge of IG/TCR gene rearrangements at diagnosis
Clonal evolution can lead to false negatives
Relative clone load quantitation is affected by the proportion of B/T lymphoid cells

B-ALL, B-cell acute lymphoblastic leukemia; IG/TCR, immunoglobulin/T-cell receptor; LAIP, leukemia-associated immunophenotype; MRD, minimal residual disease; RQ-PCR, real-time quantitative polymerase chain reaction; T-ALL, T-cell acute lymphoblastic leukemia

Clin Pediatr Hematol Oncol 2020;27:87-100
© 2020 Clin Pediatr Hematol Oncol