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 | ||
| 10−4-10−5 | 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 |
90-95% | High sensitivity | Long turnaround time |
| 10−4-10−5 | Wide applicability | Generation of patient-specific allele specific oligonucleotide primer sets is cumbersome | |
| Standardized protocol and data interpretation | Requires prior knowledge of |
||
| 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;