Prognostic impact of activation-induced cytidine deaminase expression for patients with diffuse large B-cell lymphoma

Activation-induced cytidine deaminase (AID) plays important roles in the development of diffuse large B-cell lymphoma (DLBCL); however, its prognostic value remains controversial. Here, we evaluated AID expression in 71 DLBCL patients treated with R-CHOP by immunohistochemistry and investigated its prognostic significance. AID expression was detected in 40.8% of DLBCL samples and associated with IRF4 expression. Notably, AID expression correlated with shorter progression-free survival and overall survival for patients with high (3-5) international prognostic index (IPI) score. Moreover, it was a strong predictor of poor overall response to salvage therapy after relapse or disease progression, which may suggest its role in promoting the evolution of tumors into highly refractory disease at relapse. Our findings indicate that AID expression effectively discriminates between IPI-high score patients with different survival outcomes, and suggest that initial disease control would be particularly important for the treatment of IPI-high score patients with AID-positive DLBCL.