MYD88 expression and L265P mutation in mature B-cell non-Hodgkin lymphomas.

Abstract

Myeloid differentiation primary response 88 (MYD88) is a common adaptor protein that is responsible for signaling from several receptors; mutations in this gene may play a role in the pathogenesis of lymphoma. We aimed to determine the MYD88 L265P mutation frequency, the level of MYD88 expression, and their associations with clinicopathological parameters in mature B-cell non-Hodgkin lymphomas (NHLs). A total of 68 patients were included in the study. The presence of the MYD88 L265P mutation was analyzed by real-time polymerase chain reaction and direct sequencing. MYD88 protein expression was evaluated by immunohistochemistry (IHC) using two different scoring systems. MYD88 L265P mutation was present in eight (18.6%) diffuse large B-cell lymphoma (DLBCL) patients. We also observed a significant association between the loss of MYD88 expression and advanced stage in both mature B-cell NHL and DLBCL according to the first IHC scoring systems (p=0.015 and p=0.024, respectively). An association was also seen between MYD88 overexpression and low clinical risk in both mature B-cell NHL and DLBCL according to the second IHC scoring system (p=0.027 and p=0.024, respectively). The L265P mutation may be helpful for understanding the pathogenesis of immune-privileged site-associated DLBCLs. The presence of the mutation, together with its protein overexpression, could also be used as a prognostic marker in advanced stage DLBCLs.