Detection of MYD88 L265P mutation by next-generation deep sequencing in peripheral blood mononuclear cells of Waldenstrom's macroglobulinemia and IgM monoclonal gammopathy of undetermined significance

We investigated the feasibility of using next-generation sequencing (NGS) technique using molecular barcoding technology to detect MYD88 L265P mutation in unselected peripheral blood mononuclear cells (PBMCs) in 52 patients with Waldenstrom's macroglobulinemia [1] and 21 patients with IgM-monoclonal gammopathy of undetermined significance (MGUS). The NGS technique successfully detected the MYD88 L265P in unselected PBMCs at a sensitivity of 0.02%, which was x5 higher than that of AS-PCR. All the results between paired BM and PB samples from 2 IgM MGUS and 4 untreated WMpatients matched completely. MYD88 L265P mutation was detected in 14/21 (66.7%), 14/19 (73.7%), and 10/33 (30.3%) with the median mutant allele burden of 0.36% (range, 0.06-2.85%), 0.48% (range, 0.02-32.3%), and 0.16% (range, 0.02-33.8%), in IgM-MGUS, untreated WM, and previously treated WM, respectively. Multiple linear regression analysis identified an absolute peripheral lymphocyte count as the positive predictor of PB mutant allele burden (R2 = 0,72, P<0.0001). Our non-invasive, simple NGS method has the potential to detect MYD88 L265P mutations in PBMCs of IgM MGUS and WM patients, which may especially utilized for monitoring minimal residual tumor burden after treatment.