title: Monitoring of minimal residual disease in children with acute promyelocytic leukemia by RT-PCR detecting PML/RARalpha chimeric gene: a retrospective study of clinical feasibility.
abstract: We studied retrospectively the clinical feasibility of minimal residual disease (MRD) monitoring by reverse transcription-polymerase chain reaction (RT-PCR) detecting the PML/retinoic acid receptor alpha (RARalpha) chimeric gene in children with acute promyelocytic leukemia (APL). MRD monitoring of APL was performed with standard and nested RT-PCR for PML/RARalpha gene, the sensitivity of which was 1 leukemic cell in 10(3)-10(4) and 1 in 10(4)-10(5) cells, respectively. Patients were nine children with APL (average age: 8.3 year; average period of follow-up: 69.2 months) who, after achieving remission with all-trans retinoic acid (ATRA), received treatment either with multidrug chemotherapy or with a combination of chemotherapy and ATRA. Out of six patients treated with multidrug-combined chemotherapy, two patients exhibited PCR positivity after six months of post- remission therapy, which shifted from the detectable range of the nested PCR to that of the standard PCR. These two patients subsequently relapsed and, together with two of the other patients receiving multidrug-combined chemotherapy, underwent allogeneic bone marrow transplantation. No MRD was detected in these patients after transplantation. In the remaining three patients who underwent cyclic treatment with alternative chemotherapy and ATRA, two showed positive RT-PCR at the nested or standard level, respectively, after six months of combined therapy, and one of them relapsed. Overall, three of four patients with MRD detected in post-remission period ultimately relapsed, while all of five patients without detectable MRD had a good prognosis. These findings suggest that impending relapse may be predicted by the detection of preceding PCR positivity with an increasing quantity of the PML/RARalpha mRNA that appears beyond six months of post-remission chemotherapy, with or without combined ATRA therapy.
authors.affiliation: Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Imaizumi
authors.forename: A
authors.initials: A
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Yoshinari
authors.forename: T
authors.initials: T
authors.lastname: Rikiishi
authors.forename: M
authors.initials: M
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Takano
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.forename: Y
authors.initials: Y
authors.lastname: Hatae
authors.forename: T
authors.initials: T
authors.lastname: Fujimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Hayashi
authors.forename: K
authors.initials: K
authors.lastname: Iinuma
mesh_terms: D000293:Adolescent; D000483:Alleles; D001853:Bone Marrow / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D017931:DNA Primers; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics* / Q000473:pathology; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D018168:Receptors, Retinoic Acid / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics*; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; D011993:Recombinant Fusion Proteins