A rare CD5-positive subgroup of diffuse large B-cell lymphoma – clinical, morphological and immunophenotypic features in Polish patients

The aim of the study was to assess the incidence of CD5-positive diffuse large B-cell lymphoma (DLBCL) in the Polish population and to describe its morphologic and clinical characteristics. The study included 36 patients with CD5-positive DLBCL, diagnosed and treated in the Maria Skłodowska-Curie Institute and Oncology Centre, Warsaw, Poland and the Medical University of Warsaw, Poland in the years 2002-2013. The control group consisted of 28 patients with CD5-negative DLBCL. CD5-positive DLBCL accounted for 6.26% of all DLBCL cases diagnosed in the Maria Skłodowska-Curie Institute and Oncology Centre in the years 2008-2012. The incidence is comparable to other European countries, lower than noted in Japan and higher than in the US. Patients with CD5-positive DLBCL, in comparison to the CD5-negative group, were characterized by: (1) older age (≥ 60 vs. younger) and worse general status (ECOG ≥ 2 vs. < 2), (2) lower frequency of complete remission (CR), (3) higher expression of unfavorable prognostic factors (BCL2, FOXP1, CD44) and MMP-9, and (4) lower expression of favorable prognostic factors (CD30, cyclin D1, cyclin D3) and TIMP-2.