Samples from diagnostic and remission BM or PB underwent DNA extraction using the AllPrep Extraction Kit (Qiagen). The integrity of the samples was confirmed by visualization on a 0.8% agarose gel. All samples then underwent targeted exome capture sequencing, which included the entire coding region of KIT, as previously described.(31 (link)) Samples from relapse specimens underwent analysis of mutations of exon 8 and 17 using amplification by genomic PCR as previously described.(19 (link))