title: Flow Cytometric Measurement of Blood Cells with BCR-ABL1 Fusion Protein in Chronic Myeloid Leukemia.
abstract: Chronic myeloid leukemia (CML) is characterized in the majority of cases by a t(9;22)(q34;q11) translocation, also called the Philadelphia chromosome, giving rise to the BCR-ABL1 fusion protein. Current treatment with tyrosine kinase inhibitors is directed against the constitutively active ABL1 domain of the fusion protein, and minimal residual disease (MRD) after therapy is monitored by real-time quantitative PCR (RQ-PCR) of the fusion transcript. Here, we describe a novel approach to detect and enumerate cells positive for the BCR-ABL1 fusion protein by combining the in situ proximity ligation assay with flow cytometry as readout (PLA-flow). By targeting of the BCR and ABL1 parts of the fusion protein with one antibody each, and creating strong fluorescent signals through rolling circle amplification, PLA-flow allowed sensitive detection of cells positive for the BCR-ABL1 fusion at frequencies as low as one in 10,000. Importantly, the flow cytometric results correlated strongly to those of RQ-PCR, both in diagnostic testing and for MRD measurements over time. In summary, we believe this flow cytometry-based method can serve as an attractive approach for routine measurement of cells harboring BCR-ABL1 fusions, also allowing simultaneously assessment of other cell surface markers as well as sensitive longitudinal follow-up.
authors.affiliation: Dept. of Immunology, Genetics & Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Liza
authors.initials: L
authors.lastname: Löf
authors.affiliation: Dept. of Immunology, Genetics & Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Linda
authors.initials: L
authors.lastname: Arngården
authors.affiliation: Dept. of Medical Science and Division of Hematology, University Hospital, Uppsala, Sweden.
authors.forename: Ulla
authors.initials: U
authors.lastname: Olsson-Strömberg
authors.affiliation: Department of Anthropology, University of Vienna, Vienna, Austria.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Siart
authors.affiliation: Dept. of Immunology, Genetics & Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Jansson
authors.affiliation: Dept. of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Joakim S
authors.identifier: http://orcid.org/0000-0003-3007-9875
authors.initials: JS
authors.lastname: Dahlin
authors.affiliation: Dept. of Immunology, Genetics & Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Thörn
authors.affiliation: Dept. of Immunology, Genetics & Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Lisa
authors.initials: L
authors.lastname: Christiansson
authors.affiliation: Dept. of Immunology, Genetics & Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Monica
authors.initials: M
authors.lastname: Hermansson
authors.affiliation: Dept. of Medical Science and Division of Biochemical Structure and Function, University Hospital, Uppsala, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Larsson
authors.affiliation: Dept. of Medicine, Division of Hematology, Örebro University Hospital, Örebro, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Ahlstrand
authors.affiliation: Dept. of Medicine, Division of Hematology, Örebro University Hospital, Örebro, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Wålinder
authors.affiliation: Dept. of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden.
authors.forename: Ola
authors.identifier: http://orcid.org/0000-0003-2883-1925
authors.initials: O
authors.lastname: Söderberg
authors.affiliation: Dept. of Immunology, Genetics & Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Richard
authors.initials: R
authors.lastname: Rosenquist
authors.affiliation: Dept. of Immunology, Genetics & Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Ulf
authors.identifier: http://orcid.org/0000-0002-7820-1000
authors.initials: U
authors.lastname: Landegren
authors.affiliation: Dept. of Immunology, Genetics & Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden. masood.kamali@igp.uu.se.
authors.forename: Masood
authors.initials: M
authors.lastname: Kamali-Moghaddam
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism; D015415:Biomarkers; D001773:Blood Cells / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D005434:Flow Cytometry / Q000379:methods; D005455:Fluorescent Antibody Technique; D016044:Fusion Proteins, bcr-abl / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000473:pathology
chemical_list: D018952:Antigens, CD34; D015415:Biomarkers; D016044:Fusion Proteins, bcr-abl