• Marzia Varettoni, Luca Arcaini, Silvia Zibellini, Emanuela Boveri, Sara Rattotti, Roberta Riboni, Alessandro Corso, Ester Orlandi, Maurizio Bonfichi, Manuel Gotti, Cristiana Pascutto, Silvia Mangiacavalli, Giorgio Croci, Valeria Fiaccadori, Lucia Morello, Maria Luisa Guerrera, Marco Paulli, and Mario Cazzola.
• Department of Hematology Oncology, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy. m.varettoni@smatteo.pv.it
• Blood. 2013 Mar 28;121(13):2522-8.

AbstractA study has shown that MYD88 (L265P) is a recurring somatic mutation in Waldenström's macroglobulinemia (WM). We developed an allele-specific polymerase chain reaction (PCR) for this mutation, and analyzed bone marrow or peripheral blood samples from 58 patients with WM, 77 with IgM monoclonal gammopathy of undetermined significance (IgM-MGUS), 84 with splenic marginal zone lymphoma (SMZL), and 52 with B-cell chronic lymphoproliferative disorders (B-CLPD). MYD88 (L265P) was detected in 58/58 (100%) patients with WM, 36/77 (47%) with IgM-MGUS, 5/84 (6%) with SMZL, and 3/52 (4%) with B-CLPD. Compared to IgM-MGUS patients with wild-type MYD88, those carrying MYD88 (L265P) showed significantly higher levels of IgM (P < .0001) and presented Bence-Jones proteinuria more frequently at diagnosis (P = .002). During follow-up, 9 patients with IgM-MGUS progressed to WM or to marginal zone lymphoma. Using a case-control approach, the risk of evolution of patients carrying MYD88 (L265P) was significantly higher than that of patients with wild-type MYD88 (odds ratio 4.7, 95% confidence interval 0.8 to 48.7, P = .047). These findings indicate that the allele-specific PCR we developed is a useful diagnostic tool for patients with WM or IgM-MGUS. In this latter condition, MYD88 (L265P) is associated with greater disease burden and higher risk of disease progression, and the mutation may therefore also represent a useful prognostic marker.

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