MYD88 and diffuse large B-cell lymphoma: Of note, mutations in TP53 or MYD88 recently reported to occur in 31% and 31% of IgM gammopathy–positive DLBCL [10], were observed in 13% and 20% of lymphomas with IgM gammopathy as compared to 11% and 17% of cases without IgM gammopathy.