Quantitative monitoring of the T315I mutation in patients with chronic myeloid leukemia (CML).

Tyrosine kinase inhibitors (TKIs) have dramatically improved the treatment of chronic myeloid leukemia (CML). However, resistances are occasionally observed, mainly due to mutations within the BCR-ABL kinase domain. The T315I substitution confers complete resistance to TKIs commonly used in clinical practice. In the present study, we used an allele-specific quantitative-RT-PCR to perform a molecular follow-up of BCR-ABL transcripts harboring the T315I mutation. We retrospectively quantified BCR-ABL315I mRNA in five patients who acquired the T315I mutation. Our results highlight the relevance of allele-specific Q-RT-PCR experiments for the monitoring of mutated BCR-ABL transcripts and suggest that the kinetics of emergence of T315I mutant mRNA is influenced by the stage of the disease and the presence of previous BCR-ABL kinase domain mutations.