Low prevalence of the BCR–ABL1 fusion gene in a normal population in southern Sarawak
The BCR–ABL1 fusion gene is the driver mutation of Philadelphia chromosome-positive chronic myeloid leukemia (CML). Its expression level in CML patients is monitored by a real-time quantitative polymerase chain reaction defined by the International Scale (qPCRIS). BCR–ABL1 has also been found in asymptomatic normal individuals using a non-qPCRIS method. In the present study, we examined the prevalence of BCR–ABL1 in a normal population in southern Sarawak by performing qPCRIS for BCR–ABL1 with ABL1 as an internal control on total white blood cells, using an unbiased sampling method. While 146 of 190 (76.8%) or 102 of 190 (53.7%) samples showed sufficient amplification of the ABL1 gene at > 20,000 or > 100,000 copy numbers, respectively, in qPCRIS, one of the 190 samples showed amplification of BCR–ABL1 with positive qPCRIS of 0.0023% and 0.0032% in two independent experiments, the sequence of which was the BCR–ABL1 e13a2 transcript. Thus, we herein demonstrated that the BCR–ABL1 fusion gene is expected to be present in approximately 0.5–1% of normal individuals in southern Sarawak.
KeywordsChronic myeloid leukemia Asymptomatic people Clonal hematopoiesis
We would like to thank Dr. Sai Peng Sim for allowing the usage of the Medical Molecular Genetic Laboratory, UNIMAS and supporting the study, Dr. Yuwana Podin for allowing the storage of RNA samples at the Institute of Health and Community Medicine, UNIMAS, staff from IRCMS, Kumamoto University and FMHS, UNIMAS for assisting this study. We also would like to thank Dr. Jameela Sathar and Phan Chin Lee from Ampang Hospital, Malaysia for assessing the RT-PCR data by NRL. This study was supported by the Japan Society for the Promotion of Science (JSPS) RONPAKU (Dissertation PhD) Program FY2017, UNIMAS Special Grant Scheme no: F05/SpGS/1401/16/2, Fundamental Research Grant Scheme no: FRGS/SKK01(01)/1290/2015(7) and FMHS, UNIMAS under Research no: FPSK/FPI/(F09)/2017/(14).
JWK conceived, designed, planned, and conducted the entire research, collected, analyzed, and interpreted the data, and wrote the manuscript. ATS designed, planned, and conducted samplings and provided statistical consultation. SPT conducted two of the samplings and performed FBC and smears of PB films. IFL supervised/supported blood lysis and RNA extraction. SK provided technical consultation on qPCR and performed validation of the positive subject. LS supervised and supported the research. MO co-supervised the research and provided technical support. GS supervised the research, provided technical support and consultation, and wrote the manuscript. All authors participated in revising the manuscript and its final approval.
Compliance with ethical standards
Conflict of interest
All authors declared no conflicts of interest.
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