Zac Chatterton1, Daniel Burke2, Kerry R Emslie2, Jeffery M Craig3, Jane Ng4, David M Ashley5, Francoise Mechinaud6, Richard Saffery4, Nicholas C Wong7. 1. Cancer and Disease Epigenetics and Department of Paediatrics, University of Melbourne, Melbourne, Australia; current address: Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY; zac.chatterton@mssm.edu. 2. National Measurement Institute, Sydney, Australia; 3. Developmental Epigenetics, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia; 4. Cancer and Disease Epigenetics and Department of Paediatrics, University of Melbourne, Melbourne, Australia; 5. Andrew Love Cancer Centre, Deakin University, Victoria, Australia; 6. Children's Cancer Centre, Royal Children's Hospital, Victoria, Australia; 7. Cancer and Disease Epigenetics and Department of Paediatrics, University of Melbourne, Melbourne, Australia; current address: Ludwig Institute of Cancer Research, Olivia Newton-John Cancer and Wellness Centre, Austin Hospital, Heidelberg, Victoria, Australia.
Abstract
BACKGROUND: DNA methylation biomarkers capable of diagnosis and subtyping have been found for many cancers. Fifteen such markers have previously been identified for pediatric acute lymphoblastic leukemia (ALL). Validation of these markers is necessary to assess their clinical utility for molecular diagnostics. Substantial efficiencies could be achieved with these DNA methylation markers for disease tracking with potential to replace patient-specific genetic testing. METHODS: We evaluated DNA methylation of promoter regions of TLX3 (T-cell leukemia homeobox) and FOXE3 (forkhead box E3) in bone marrow biopsies from 197 patients classified as leukemic (n = 95) or clear of the disease (n = 102) by MALDI-TOF. Using a single nucleotide extension assay (methylSABER), we tested 10 bone marrow biopsies collected throughout the course of patient chemotherapy. Using reference materials, diagnostic thresholds and limits of detection were characterized for both methods. RESULTS: Reliable detection of DNA methylation of TLX3 and FOXE3 segregated ALL from those clear of disease with minimal false-negative and false-positive results. The limit of detection with MALDI-TOF was 1000-5000 copies of methylated allele. For methylSABER, the limit of detection was 10 copies of methylated TLX3, which enabled monitoring of minimal residual disease in ALL patients. CONCLUSIONS: Mass spectrometry procedures can be used to regionally multiplex and detect rare DNA methylation events, establish DNA methylation loci as clinically applicable biomarkers for disease diagnosis, and track pediatric ALL.
BACKGROUND: DNA methylation biomarkers capable of diagnosis and subtyping have been found for many cancers. Fifteen such markers have previously been identified for pediatric acute lymphoblastic leukemia (ALL). Validation of these markers is necessary to assess their clinical utility for molecular diagnostics. Substantial efficiencies could be achieved with these DNA methylation markers for disease tracking with potential to replace patient-specific genetic testing. METHODS: We evaluated DNA methylation of promoter regions of TLX3 (T-cell leukemia homeobox) and FOXE3 (forkhead box E3) in bone marrow biopsies from 197 patients classified as leukemic (n = 95) or clear of the disease (n = 102) by MALDI-TOF. Using a single nucleotide extension assay (methylSABER), we tested 10 bone marrow biopsies collected throughout the course of patient chemotherapy. Using reference materials, diagnostic thresholds and limits of detection were characterized for both methods. RESULTS: Reliable detection of DNA methylation of TLX3 and FOXE3 segregated ALL from those clear of disease with minimal false-negative and false-positive results. The limit of detection with MALDI-TOF was 1000-5000 copies of methylated allele. For methylSABER, the limit of detection was 10 copies of methylated TLX3, which enabled monitoring of minimal residual disease in ALL patients. CONCLUSIONS: Mass spectrometry procedures can be used to regionally multiplex and detect rare DNA methylation events, establish DNA methylation loci as clinically applicable biomarkers for disease diagnosis, and track pediatric ALL.
Authors: Gerald B W Wertheim; Catherine Smith; Marlise Luskin; Alison Rager; Maria E Figueroa; Martin Carroll; Stephen R Master Journal: Clin Chem Date: 2014-10-27 Impact factor: 8.327