TY - JOUR
T1 - Reverse transcription with random pentadecamer primers improves the detection limit of a quantitative PCR assay for BCR-ABL transcripts in chronic myeloid leukemia
T2 - Implications for defining sensitivity in minimal residual disease
AU - Ross, David M.
AU - Watkins, Dale B.
AU - Hughes, Timothy
AU - Branford, Susan
N1 - Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2008/8/9
Y1 - 2008/8/9
N2 - BACKGROUND: Real-time quantitative reverse transcription PCR (RQ-PCR) assay for BCR-ABL is used to monitor treatment response in chronic myeloid leukemia (CML). BCR-ABL transcript levels decline over several years of imatinib treatment, and increasing numbers of patients have BCR-ABL transcripts at or below the limit of detection. More sensitive PCR methods are required to assess whether these patients have a long-term continuing decline in residual disease. METHODS: We used random pentadecamer (R15) primers for reverse transcription in RQ-PCR and compared the results with our established method that uses random hexamers. An increase in assay sensitivity would be detected as an increase in the number of BCR-ABL transcripts. RESULTS: BCR-ABL transcripts increased by 86% with R15 primers. We used R15 primers to retest 19 samples from selected CML patients who had no BCR-ABL transcripts recently detectable with hexamer primers and detected BCR-ABL transcripts in 68% of the samples. Use of R15 primers showed variable increases in the transcripts for control genes BCR (breakpoint cluster region), ABL1 (c-abl oncogene 1, receptor tyrosine kinase), and GUSB (glucuronidase, beta), depending on the gene examined. The reported BCR-ABL/control gene ratio was affected, and the estimated detection limit of the assay, which was based on increased control gene copy number, was different for each control gene. CONCLUSIONS: This simple modification to the reverse transcription methodology improved the detection limit of the RQ-PCR assay for BCR-ABL transcripts. In the field of CML, these results have important implications for defining the detection limit of an assay when the BCR-ABL transcript is undetectable. Random pentadecamer primers may also be useful in other reverse transcription PCR assays for which the abundance of the target RNA is low.
AB - BACKGROUND: Real-time quantitative reverse transcription PCR (RQ-PCR) assay for BCR-ABL is used to monitor treatment response in chronic myeloid leukemia (CML). BCR-ABL transcript levels decline over several years of imatinib treatment, and increasing numbers of patients have BCR-ABL transcripts at or below the limit of detection. More sensitive PCR methods are required to assess whether these patients have a long-term continuing decline in residual disease. METHODS: We used random pentadecamer (R15) primers for reverse transcription in RQ-PCR and compared the results with our established method that uses random hexamers. An increase in assay sensitivity would be detected as an increase in the number of BCR-ABL transcripts. RESULTS: BCR-ABL transcripts increased by 86% with R15 primers. We used R15 primers to retest 19 samples from selected CML patients who had no BCR-ABL transcripts recently detectable with hexamer primers and detected BCR-ABL transcripts in 68% of the samples. Use of R15 primers showed variable increases in the transcripts for control genes BCR (breakpoint cluster region), ABL1 (c-abl oncogene 1, receptor tyrosine kinase), and GUSB (glucuronidase, beta), depending on the gene examined. The reported BCR-ABL/control gene ratio was affected, and the estimated detection limit of the assay, which was based on increased control gene copy number, was different for each control gene. CONCLUSIONS: This simple modification to the reverse transcription methodology improved the detection limit of the RQ-PCR assay for BCR-ABL transcripts. In the field of CML, these results have important implications for defining the detection limit of an assay when the BCR-ABL transcript is undetectable. Random pentadecamer primers may also be useful in other reverse transcription PCR assays for which the abundance of the target RNA is low.
UR - http://www.scopus.com/inward/record.url?scp=51349154265&partnerID=8YFLogxK
U2 - 10.1373/clinchem.2008.105916
DO - 10.1373/clinchem.2008.105916
M3 - Article
C2 - 18641042
AN - SCOPUS:51349154265
SN - 0009-9147
VL - 54
SP - 1568
EP - 1571
JO - Clinical chemistry
JF - Clinical chemistry
IS - 9
ER -