Evaluation of T315I mutation frequency in chronic myeloid leukemia patients after imatinib resistance

Area of Science:

• Oncology
• Hematology
• Molecular Biology

Background:

• Drug resistance, particularly mutations in the Abl kinase domain, is a major cause of treatment failure in chronic myeloid leukemia (CML).
• The T315I mutation is a critical gatekeeper mutation conferring resistance to all ATP-competitive BCR-ABL inhibitors.

Purpose of the Study:

• To evaluate the prevalence of the T315I mutation in imatinib-resistant CML patients.
• To assess the utility of an allele-specific oligonucleotide reverse transcriptase polymerase chain reaction (ASO-RT-PCR) assay for T315I mutation detection.

Main Methods:

• An allele-specific oligonucleotide reverse transcriptase polymerase chain reaction (ASO-RT-PCR) assay was employed.
• The study included a cohort of 60 imatinib-resistant CML patients across different disease phases.
• Direct sequencing was used for confirmation of positive mutation cases.

Main Results:

• The T315I mutation was detected in 7% (4/60) of the studied imatinib-resistant CML patients.
• All patients harboring the T315I mutation were in advanced disease phases (accelerated or blastic) and had lost prior treatment responses.
• The ASO-RT-PCR method proved to be a cost-effective and user-friendly tool for screening.

Conclusions:

• The T315I mutation is present in a subset of imatinib-resistant CML patients, predominantly in advanced disease stages.
• ASO-RT-PCR is a viable and economical method for screening T315I mutations in CML.
• Confirmation by direct sequencing is recommended for positive screening results to guide CML treatment strategies.