MYD88 L265P Somatic Mutation in IgM MGUS

Abstract

Treon et al. (Aug. 30 issue)¹ report that MYD88 L265P is a commonly recurring mutation in patients with Waldenström's macroglobulinemia, an IgM-secretory lymphoplasmacytic lymphoma (LPL). Indeed, 49 of 54 patients (91%) with Waldenström's macroglobulinemia and 3 of 3 patients (100%) with non–IgM-secreting LPL had MYD88 L265P expression on the basis of whole-genome sequencing, as confirmed on Sanger sequencing. In contrast, MYD88 L265P was absent in 10 patients with multiple myeloma (including 2 with IgM multiple myeloma) and was expressed in only 3 of 46 patients (7%) with marginal-zone lymphoma,¹ two entities in the differential diagnosis of Waldenström's macroglobulinemia.²