ABSTRACT
Molecular monitoring of chronic myeloid leukemia patients using robust BCR-ABL1 tests standardized to the International Scale (IS) is key to proper disease management, especially when treatment cessation is considered. Most laboratories currently use a time-consuming sample exchange process with reference laboratories for IS calibration. A World Health Organization (WHO) BCR-ABL1 reference panel was developed (MR(1)-MR(4)), but access to the material is limited. In this study, we describe the development of the first cell-based secondary reference panel that is traceable to and faithfully replicates the WHO panel, with an additional MR(4.5) level. The secondary panel was calibrated to IS using digital PCR with ABL1, BCR and GUSB as reference genes and evaluated by 44 laboratories worldwide. Interestingly, we found that >40% of BCR-ABL1 assays showed signs of inadequate optimization such as poor linearity and suboptimal PCR efficiency. Nonetheless, when optimized sample inputs were used, >60% demonstrated satisfactory IS accuracy, precision and/or MR(4.5) sensitivity, and 58% obtained IS conversion factors from the secondary reference concordant with their current values. Correlation analysis indicated no significant alterations in %BCR-ABL1 results caused by different assay configurations. More assays achieved good precision and/or sensitivity than IS accuracy, indicating the need for better IS calibration mechanisms.
Subject(s)
Fusion Proteins, bcr-abl/analysis , Calibration , Fusion Proteins, bcr-abl/standards , Genes, abl , Humans , Polymerase Chain Reaction , Proto-Oncogene Proteins c-bcr/genetics , Reference Standards , World Health OrganizationABSTRACT
The myeloproliferative diseases (MPDs) or myelo-proliferative neoplasms (MPNs) are a group of diseases of the bone marrow in which excess cells are produced. Chronic idiopathic myelofibrosis (CIMF) is a stem cell defect characterized by splenomegaly with multiorgan extramedullary hematopoiesis, immature peripheral blood granulocytes and erythrocytes and progressive bone marrow fibrosis. The most common chromosomal abnormalities seen in CIMF patients include numerical changes of chromosomes 7, 8 and 9, and structural changes of 1q, 5q, 13q and 20q. At least 75.0% of patients with bone marrow abnormalities have one or more of these chromosomal anomalies. Detection of the Janus kinase 2 (JAK2) mutation may be a potential major breakthrough for understanding the pathobiology of MPNs, and is an essential part of the diagnostic algorithm. In this study, we describe a JAK2(V617F) mutation negative CIMF patient who has the chromosomal translocation t(3;12)(q26;q21) in her karyotype.
