Utilisation of RT-PCR assay for the detection of t(9;22)BCR-ABL fusion gene mRNA in diagnosis of chronic myeloid leukaemia at the University Teaching Hospital,Lusaka, Zambia
Date
2017
Authors
Kasongo, Joseph
Journal Title
Journal ISSN
Volume Title
Publisher
University of Zambia
Abstract
Chronic MyeloidLeukaemia (CML) is consistently associated with a characteristic chromosome
translocation called the Philadelphia (Ph) chromosome. This translocation fuses sequences of
theBreakpoint Cluster Region(BCR) gene from band q11 on chromosome 22 with regions of
theAbelson(ABL) gene from band q34 on chromosome 9, resulting in the production of a
chimeric molecule, the BCR-ABL fusion mRNA product. The Philadelphia chromosome, t(9;22)
(q34; q11), is the hallmark of CML, and the discovery of this molecular pathway has resulted in
more accurate diagnosis, more targeted drug therapy and the application of molecular
methodologies for post-therapy follow-up for the presence of minimal residual disease (MRD).
Demonstration of the t(9;22) chromosomal aberration confirms the diagnosis. PCR is the most
sensitive technique available for detecting BCR-ABL gene fusion in the diagnosis of CML as
well as monitoring of CML patients on therapy and as such molecular diagnosis and monitoring
of CML patients has become clinically very important. The aim of this study was to evaluate the
utilisation of Xpert BCR-ABL Ultra, a commercially available real time quantitativeReverse
Transcriptase Polymerase Chain Reaction(RT-PCR) assay for detection and measurement of
Major BCR-ABL(p210 BCR-ABL mRNA), to routine molecular diagnosis of CML,
demonstrating that the same assay could be used both for diagnosis and monitoring in the routine
management of CML patients. A cross sectional descriptive laboratory study was undertaken at
the University Teaching Hospital in Lusaka, Zambia. The GeneXpert BCR-ABL Assay was used
with the GeneXpertDx System designed to detect the BCR-ABL p210 (b2a2 and b3a2) major
break point translocation transcript in peripheral blood specimens. A total of 15 samples were
analysed, of which 8 were known positive confirmed to have BCR-ABL by conventional PCR
assay collected from known CML patients, and 7 negative taken from healthy blood donors
using Xpert BCR-ABL Ultra Assay. Our results showed100% sensitivity, 85.7% specificity,
99.9%positive predictive value, 100% negative predictive value and 93.3% test efficiency. This
study showed that the Xpert BCR-ABL Ultra, quantitative RT-PCR assay could also be reliably
used as a diagnostic tool in the diagnosis and management of CML. This study showed that the
Xpert BCR-ABL Ultra, a commercially available real time quantitative RT-PCR assay, designed
for quantitative monitoring of CML patients undergoing Tyrosine Kinase Inhibitors therapy, can
also be reliably used as a diagnostic tool, for detection of Major BCR-ABL (p210 BCR-ABL
mRNA), in the diagnosis and management of CML. That means the same assay could be adopted
for both diagnosis and monitoring in the routine management of CML patients in Zambia.
Description
THESIS MSC
Keywords
Myeloid Leukaemia--detection BCR-ABL--Zambia