Table 7. Characteristics of the... | American Society of Hematology

Table 7.

Characteristics of the techniques currently employed for minimal residual disease (MRD) detection in acute lymphoblastic leukemia (ALL).

	Flow Cytometric Immunophenotyping	PCR Analysis of Chromosome Aberrations (mainly detection of fusion gene transcripts)	PCR Analysis of Ig/TCR Genes (junctional region specific approach)
* In childhood ALL this particularly concerns t(12;21)(TEL-AML1) and in adult ALL particularly t(9;22)(BCR-ABL).
** This mainly concerns del(1)(p32 p32) with SIL-TAL1 fusion and t(5;14) with aberrant HOX11L2 expression, together occurring in 25-35% of childhood T-ALL and in 15-20% of adult ALL.^11,¹²
Sensitivity	10^–3–10^–4	10^–4–10^–6	10^–4–10^–5
Applicability
Precursor-B-ALL	60-98%	40-45%*	90-95%
T-ALL	90-95%	15-35%**	90-95%
Advantages	applicable for most patients relatively cheap rapid: 1-2 days	relatively easy and cheap sensitive and leukemia-specific stable target during disease course rapid: 2-3 days suitable for monitoring of uniform patient groups (e.g., Ph⁺ ALL)	applicable for virtually all patients, if IGH, IGK-Kde, TCRG, and TCRD gene rearrangements are used as targets sensitive and patient-specific rapid during follow-up: 2-3 days (if junctional region is identified and if RQ-PCR is used)
Disadvantages	limited sensitivity need for preferably two aberrant immunophenotypes per patient, because of chance of immuno-phenotypic shifts	useful in only a minority of patients cross-contamination of PCR products leading to false-positive results (even at diagnosis)	time-consuming at diagnosis: identification of the junctional regions and sensitivity testing relatively expensive need for preferably two PCR targets per patient, because of chance of clonal evolution

	Flow Cytometric Immunophenotyping	PCR Analysis of Chromosome Aberrations (mainly detection of fusion gene transcripts)	PCR Analysis of Ig/TCR Genes (junctional region specific approach)
* In childhood ALL this particularly concerns t(12;21)(TEL-AML1) and in adult ALL particularly t(9;22)(BCR-ABL).
** This mainly concerns del(1)(p32 p32) with SIL-TAL1 fusion and t(5;14) with aberrant HOX11L2 expression, together occurring in 25-35% of childhood T-ALL and in 15-20% of adult ALL.^11,¹²
Sensitivity	10^–3–10^–4	10^–4–10^–6	10^–4–10^–5
Applicability
Precursor-B-ALL	60-98%	40-45%*	90-95%
T-ALL	90-95%	15-35%**	90-95%
Advantages	applicable for most patients relatively cheap rapid: 1-2 days	relatively easy and cheap sensitive and leukemia-specific stable target during disease course rapid: 2-3 days suitable for monitoring of uniform patient groups (e.g., Ph⁺ ALL)	applicable for virtually all patients, if IGH, IGK-Kde, TCRG, and TCRD gene rearrangements are used as targets sensitive and patient-specific rapid during follow-up: 2-3 days (if junctional region is identified and if RQ-PCR is used)
Disadvantages	limited sensitivity need for preferably two aberrant immunophenotypes per patient, because of chance of immuno-phenotypic shifts	useful in only a minority of patients cross-contamination of PCR products leading to false-positive results (even at diagnosis)	time-consuming at diagnosis: identification of the junctional regions and sensitivity testing relatively expensive need for preferably two PCR targets per patient, because of chance of clonal evolution