Clinical impact of CD5 expression in Korean patients with diffuse large B-cell lymphoma

BACKGROUND CD5-positive diffuse large B-cell lymphoma (CD5+ DLBCL) accounts for 5-10% of DLBCL cases and has poor patient outcomes. However, most studies on CD5+ DLBCL were performed in Japanese patients and only few data are available for Korean population. In this study, we investigated the clinical characteristics and prognostic impact of CD5 expression in Korean patients with bone marrow (BM) involvement of DLBCL. METHODS Patients who were initially diagnosed with BM involvement of de novo DLBCL from 2005 to 2013 were included. Clinicopathological features and outcomes of patients were compared between CD5+ and CD5 negative (CD5-) DLBCL. RESULTS Among a total of 57 patients, the number of patients with CD5+ and CD5- DLBCL were 13 and 44, respectively. Clinical and laboratory features of CD5+ DLBCL were not significantly different from those of CD5- DLBCL. The 3-year overall survival (OS) rates for CD5+ and CD5- DLBCL were 20.2% and 59.0%, respectively (P=0.031), and 3-year progression-free survival (PFS) rates for CD5+ and CD5- DLBCL were 23.1% and 50.1%, respectively (P=0.055). CONCLUSION CD5+ DLBCL with BM involvement showed an inferior survival tendency compared to CD5- DLBCL, and thorough evaluation of CD5 expression might be helpful to predict the prognosis of patients with DLBCL.