A new rapid and sensitive assay for detecting the T3151 BCR-ABL kinase domain mutation in chronic myeloid leukaemia

A significant minority of chronic myeloid leukaemia patients eventually develop resistance to imatinib, often as a result of point mutations within the BCR-ABL kinase domain. Second-line tyrosine kinase inhibitors (TKIs) are effective against mutations that confer imatinib resistance; however, the T3151 BCR-ABL mutant has proved resistant to all available TKIs. An assay facilitating early identification of BCR-ABL(T3151) would therefore aid in identifying high-risk patients who may benefit from alternative therapy. This report describes the development of a sensitive T3151 mutation detection methodology based on real-time PCR with self-probing fluorescent primers. The technique demonstrated complete concordance with direct sequencing, correctly identifying 34 T3151-positive samples from a total of 61 samples screened. In a limiting dilution assay, the mutated clone was detectable to a level of 1% of total cells. The data show that Scorpions PCR enables rapid screening for BCR-ABLT3151 in chronic myeloid leukaemia patients and is appropriate for use in a clinical setting.