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© 2013 Iqbal et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License: https://creativecommons.org/licenses/by/4.0/ (the “License”), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Background

BCR-ABL kinase domain mutations are infrequently detected in newly diagnosed chronic-phase chronic myeloid leukemia (CML) patients. Recent studies indicate the presence of pre-existing BCR-ABL mutations in a higher percentage of CML patients when CD34+ stem/progenitor cells are investigated using sensitive techniques, and these mutations are associated with imatinib resistance and disease progression. However, such studies were limited to smaller number of patients.

Methods

We investigated BCR-ABL kinase domain mutations in CD34+ cells from 100 chronic-phase CML patients by multiplex allele-specific PCR and sequencing at diagnosis. Mutations were re-investigated upon manifestation of imatinib resistance using allele-specific PCR and direct sequencing of BCR-ABL kinase domain.

Results

Pre-existing BCR-ABL mutations were detected in 32/100 patients and included F311L, M351T, and T315I. After a median follow-up of 30 months (range 8–48), all patients with pre-existing BCR-ABL mutations exhibited imatinib resistance. Of the 68 patients without pre-existing BCR-ABL mutations, 24 developed imatinib resistance; allele-specific PCR and BCR-ABL kinase domain sequencing detected mutations in 22 of these patients. All 32 patients with pre-existing BCR-ABL mutations had the same mutations after manifestation of imatinib-resistance. In imatinib-resistant patients without pre-existing BCR-ABL mutations, we detected F311L, M351T, Y253F, and T315I mutations. All imatinib-resistant patients except T315I and Y253F mutations responded to imatinib dose escalation.

Conclusion

Pre-existing BCR-ABL mutations can be detected in a substantial number of chronic-phase CML patients by sensitive allele-specific PCR technique using CD34+ cells. These mutations are associated with imatinib resistance if affecting drug binding directly or indirectly. After the recent approval of nilotinib, dasatinib, bosutinib and ponatinib for treatment of chronic myeloid leukemia along with imatinib, all of which vary in their effectiveness against mutated BCR-ABL forms, detection of pre-existing BCR-ABL mutations can help in selection of appropriate first-line drug therapy. Thus, mutation testing using CD34+ cells may facilitate improved, patient-tailored treatment.

Details

Title
Sensitive Detection of Pre-Existing BCR-ABL Kinase Domain Mutations in CD34+ Cells of Newly Diagnosed Chronic-Phase Chronic Myeloid Leukemia Patients Is Associated with Imatinib Resistance: Implications in the Post-Imatinib Era
Author
Iqbal, Zafar; Aleem, Aamer; Iqbal, Mudassar; Mubashar Iqbal Naqvi; Ammara Gill; Abid Sohail Taj; Qayyum, Abdul; ur-Rehman, Najeeb; Khalid, Ahmad Mukhtar; Ijaz Hussain Shah; Khalid, Muhammad; Haq, Riazul; Khan, Mahwish; Baig, Shahid Mahmood; Jamil, Abid; Muhammad Naeem Abbas; Absar, Muhammad; Amer Mahmood; Rasool, Mahmood; Akhtar, Tanveer
First page
e55717
Section
Research Article
Publication year
2013
Publication date
Feb 2013
Publisher
Public Library of Science
e-ISSN
19326203
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1330877492
Copyright
© 2013 Iqbal et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License: https://creativecommons.org/licenses/by/4.0/ (the “License”), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.