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

Abstract

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. 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. 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. 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.