1. Effect of ABCG2 , OCT1 , and ABCB1 ( MDR1 ) Gene Expression on Treatment-Free Remission in a EURO-SKI Subtrial
- Author
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Philipp J. Jost, Gabriele Prange-Krex, Wolfgang Seifarth, Tim H. Brümmendorf, Martin Müller, Joelle Guilhot, Robert Eckert, Susanne Saussele, Christian Dietz, Cornelius F. Waller, Carsten Janβen, Birgit Spiess, Viktor Janzen, Gerd Büschel, Sebastien Rinaldetti, Philippe Schafhausen, Markus Pfirrmann, Stefan Hanzel, Martine Klausmann, Panayiotidis Panagiotidis, Jolanta Dengler, Kirsi Manz, Maria Elisabeth Goebeler, Maria Pagoni, Regina Herbst, Wolf-Karsten Hofmann, Thomas Illmer, Maria Dimou, Alice Fabarius, Alexander Kiani, Andreas Burchert, and Francois-Xavier Mahon
- Subjects
Adult ,Male ,0301 basic medicine ,Oncology ,Cancer Research ,medicine.medical_specialty ,ATP Binding Cassette Transporter, Subfamily B ,Pharmacogenomic Variants ,medicine.drug_class ,Antineoplastic Agents ,Context (language use) ,Kaplan-Meier Estimate ,Disease-Free Survival ,Tyrosine-kinase inhibitor ,03 medical and health sciences ,0302 clinical medicine ,Leukemia, Myelogenous, Chronic, BCR-ABL Positive ,Internal medicine ,Gene expression ,Biomarkers, Tumor ,ATP Binding Cassette Transporter, Subfamily G, Member 2 ,Humans ,Medicine ,ddc:610 ,Protein Kinase Inhibitors ,Aged ,Aged, 80 and over ,business.industry ,Proportional hazards model ,Remission Induction ,Hazard ratio ,Myeloid leukemia ,Hematology ,Middle Aged ,ddc ,Neoplasm Proteins ,Discontinuation ,030104 developmental biology ,030220 oncology & carcinogenesis ,Female ,Transcriptome ,business ,Pharmacogenetics ,Octamer Transcription Factor-1 - Abstract
Within the EURO-SKI trial, 132 chronic phase CML patients discontinued imatinib treatment. RNA was isolated from peripheral blood in order to analyze the expression of MDR1, ABCG2 and OCT1. ABCG2 was predictive for treatment-free remission in Cox regression analysis. High transcript levels of the ABCG2 efflux transporter (>4.5 parts per thousand) were associated with a twofold higher risk of relapse. Introduction: Tyrosine kinase inhibitors (TKIs) can safely be discontinued in chronic myeloid leukemia (CML) patients with sustained deep molecular response. ABCG2 (breast cancer resistance protein), OCT1 (organic cation transporter 1), and ABCB1 (multidrug resistance protein 1) gene products are known to play a crucial role in acquired pharmacogenetic TKI resistance. Their influence on treatment-free remission (TFR) has not yet been investigated. Materials and Methods: RNA was isolated on the last day of TKI intake from peripheral blood leukocytes of 132 chronic phase CML patients who discontinued TKI treatment within the European Stop Tyrosine Kinase Inhibitor Study trial. Plasmid standards were designed including subgenic inserts of OCT1, ABCG2, and ABCB1 together with GUSB as reference gene. For expression analyses, quantitative real-time polymerase chain reaction was used. Multiple Cox regression analysis was performed. In addition, gene expression cutoffs for patient risk stratification were investigated. Results: The TFR rate of 132 patients, 12 months after TKI discontinuation, was 54% (95% confidence interval [CI], 46%-62%). ABCG2 expression (parts per thousand) was retained as the only significant variable (P=.02; hazard ratio, 1.04; 95% CI, 1.01-1.07) in multiple Cox regression analysis. Only for the ABCG2 efflux transporter, a significant cutoff was found (P=.04). Patients with an ABCG2/GUSB transcript level >4.5 parts per thousand (n=93) showed a 12-month TFR rate of 47% (95% CI, 37%-57%), whereas patients with low ABCG2 expression (
- Published
- 2018
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