title: Prospective molecular monitoring of BCR/ABL transcript in children with Ph+ acute lymphoblastic leukaemia unravels differences in treatment response.
abstract: Children with Philadelphia-chromosome-positive (Ph+) acute lymphoblastic leukaemia (ALL) represent a subgroup at very high risk for treatment failure, despite intensive chemotherapy. However, recent retrospective studies showed that Ph+ childhood ALL is a heterogeneous disease with regard to treatment response. We have prospectively monitored, by reverse transcription polymerase chain reaction (RT-PCR) during follow-up, the presence of the BCR/ABL fusion transcript in Ph+ ALL children diagnosed in the Italian multicentre Associazione Italiana Ematologia Oncologia Pediatrica ALL-AIEOP-95 therapy protocol. To our knowledge, this is the first report on the evaluation of minimal residual disease (MRD) in childhood Ph+ ALL prospectively enrolled in an intensive, Berlin-Frankfurt-Munster (BFM)-type treatment protocol. Twenty-seven of 36 (75.0%) Ph+ patients consecutively enrolled into the high-risk group of the AIEOP-ALL protocol between May 1995 and October 1999 were successfully analysed. Twenty were good responders to the pre-phase of prednisone/intrathecal methotrexate treatment (PGR) and seven were poor responders (PPR). Within the PPR group, the RT-PCR monitoring constantly showed positivity for the BCR/ABL fusion transcript and all the patients died of disease progression. In contrast, highly sensitive qualitative RT-PCR monitoring revealed heterogeneity within the PGR group of Ph+ childhood ALL patients. Three different subgroups could be defined, according to the clearance of Ph+ cells within the first 5 months of treatment. This provides useful information on the capability of chemotherapy to reduce the leukaemic clone, with prognostic implications.
authors.affiliation: Centro Ricerca M. Tettamanti, Clinica Pediatrica Università di Milano Bicocca, Monza, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Cazzaniga
authors.forename: Marina
authors.initials: M
authors.lastname: Lanciotti
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Rossi
authors.forename: Daniela
authors.initials: D
authors.lastname: Di Martino
authors.forename: Maurizio
authors.initials: M
authors.lastname: Aricò
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Valsecchi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Basso
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Masera
authors.forename: Concetta
authors.initials: C
authors.lastname: Micalizzi
authors.forename: Andrea
authors.initials: A
authors.lastname: Biondi
mesh_terms: D000293:Adolescent; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D006801:Humans; D007223:Infant; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000401:mortality; D008297:Male; D008727:Methotrexate / Q000008:administration & dosage; D018365:Neoplasm, Residual / Q000235:genetics*; D011241:Prednisone / Q000008:administration & dosage; D011446:Prospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016896:Treatment Outcome
chemical_list: D016044:Fusion Proteins, bcr-abl; D011241:Prednisone; D008727:Methotrexate