Natini JinawathAlexis Norris-KirbyB. Douglas SmithChristopher D. GockeDenise A. BatistaConstance A. GriffinKathleen M. MurphyJohns Hopkins Medical InstitutionsMahidol UniversityPark Bldg.2018-09-132018-09-132009-01-01Journal of Molecular Diagnostics. Vol.11, No.4 (2009), 359-363152515782-s2.0-69249097923https://repository.li.mahidol.ac.th/handle/123456789/27333Patients with chronic myelogenous leukemia have a t(9;22)(q34;q11.2) or variant translocation that results in a BCR-ABL fusion gene. BCR-ABL detection by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) is the standard practice for monitoring residual disease in patients with chronic myelogenous leukemia who receive tyrosine kinase inhibitor therapies. In this study, we describe a patient who tested positive for the BCR-ABL translocation by fluorescence in situ hybridization and cytogenetic analysis but tested negative by qRT-PCR molecular analysis at the time of diagnosis. Further PCR analysis and DNA sequencing with alternative primer sets demonstrated the presence of an e14a3 (also known as b3a3) BCR-ABL fusion. The e14a3 fusion is rare, but may be underreported as a result of many commercially available and laboratory-developed primer sets that fail to detect breakpoints in the ABL gene that are downstream of intron 1. For this patient, if the qRT-PCR assay had been used to monitor disease response/progression after treatment and not in conjunction with fluorescence in situ hybridization or cytogenetics at the time of diagnosis, the negative result would have been misinterpreted as molecular remission. Copyright © American Society for Investigative Pathology and the Association for Molecular Pathology.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyMedicineArticleSCOPUS10.2353/jmoldx.2009.090008