Droplet digital polymerase chain reaction improves the detection of BCR-ABL1 kinase domain mutation in Philadelphia chromosome-positive acute lymphoblastic leukemia

Abstract

Introduction: Sanger sequencing (SS) is the most frequently used method for detecting ABL1 kinase domain (KD) mutations in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph⁺ ALL). However, it cannot detect low levels of mutation. Recently, droplet digital polymerase chain reaction (ddPCR) has been developed as a sensitive technique for detecting mutations in hematological neoplasms. The aim of our study was to explore the value of ddPCR in detecting ABL1 KD mutations.

Methods: We compared the results of SS and ddPCR in detecting ABL1 KD mutations in a consecutive cohort of 65 adolescent and adult patients with Ph⁺ ALL treated with intensive multiagent chemotherapy plus TKIs.

Results: At diagnosis, SS and ddPCR identified 1 (1.5%) and 26 (40%) out of 65 patients with positive ABL1 KD mutations, respectively. Patients with T315I mutations detected by ddPCR at diagnosis all developed SS-detectable T315I mutations during treatment with first- or second-generation TKIs, and non-T315I mutations detected by ddPCR at diagnosis displayed a limited prognostic impact.

Conclusion: Our study demonstrates that ddPCR is a highly sensitive and accurate mutation detection method and the presence of T315I mutations before treatment shows prognostic significance in the context of first- or second-generation TKIs.

Keywords: BCR-ABL1; acute lymphoblastic leukemia; droplet digital PCR; mutations; sanger sequencing; tyrosine kinase inhibitors.