MYD88 and plasma cell myeloma: The MYD88 L265P mutation is highly frequently observed in the bone marrow (BM) from patients with WM, and relatively frequently in the BM from MGUS patients, while absent in multiple myeloma patients.[25] In our series, we found this mutation to be significantly overrepresented in families with a family history of WM relative to families with a family history of MM, consistent with the observation in BM samples in previous studies.