title: Selecting and deselecting imatinib-resistant clones: observations made by longitudinal, quantitative monitoring of mutated BCR-ABL.
abstract: Resistance to imatinib during the treatment of chronic myeloid leukaemia (CML) is frequently associated with point mutations in the ABL gene encoding the ATP binding region likely to cause disease relapse. Early diagnosis and monitoring of these mutations may be important in order to prevent rapid expansion of resistant clones. We describe a quantitative mutation-specific PCR assay based on the readily available Taqman platform. Selectivity for the mutated target is conferred by mutation-specific primers destabilised by additional mismatches. The assay can be carried out in parallel to standard BCR-ABL quantification and is therefore more quickly compared to standard sequencing procedures. The sensitivity of the assay reaches 0.1%. It also allows for quantitative assessment of mutated clones. By analysing sequential samples of resistant subjects, we show how mutated clones were selected, maintained or deselected depending on the individual treatment setting. The high sensitivity and practical merits of this method makes it a good candidate for prospective molecular surveillance of patients at high risk for imatinib resistance.
authors.affiliation: Department of Immunology and Transfusion Medicine, University Hospital of Northern Norway, University of Tromsø, Tromsø, Norway. franz.gruber@unn.no
authors.forename: F X E
authors.initials: FX
authors.lastname: Gruber
authors.forename: T
authors.initials: T
authors.lastname: Lamark
authors.forename: A
authors.initials: A
authors.lastname: Anonli
authors.forename: M A
authors.initials: MA
authors.lastname: Sovershaev
authors.forename: M
authors.initials: M
authors.lastname: Olsen
authors.forename: T
authors.initials: T
authors.lastname: Gedde-Dahl
authors.forename: H
authors.initials: H
authors.lastname: Hjort-Hansen
authors.forename: B
authors.initials: B
authors.lastname: Skogen
mesh_terms: D000328:Adult; D000368:Aged; D001549:Benzamides; D002999:Clone Cells / Q000187:drug effects; D004252:DNA Mutational Analysis / Q000379:methods / Q000592:standards; D017931:DNA Primers; D019008:Drug Resistance, Neoplasm; D016044:Fusion Proteins, bcr-abl / Q000032:analysis* / Q000235:genetics; D006801:Humans; D000068877:Imatinib Mesylate; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000175:diagnosis / Q000473:pathology*; D008137:Longitudinal Studies; D008722:Methods; D008875:Middle Aged; D010879:Piperazines / Q000494:pharmacology*; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods / Q000592:standards; D011743:Pyrimidines / Q000494:pharmacology*
chemical_list: D001549:Benzamides; D017931:DNA Primers; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D016044:Fusion Proteins, bcr-abl