Programmed death ligand 1 expression in diffuse large B cell lymphoma: correlation with clinicopathological prognostic factors

Background The prognostic value of the level of programmed death ligand 1 (PD-L1) expression in non-Hodgkin lymphoma (NHL) is still debatable. This study examined the effect of the level of PD-L1 expression on the clinicopathological characteristics and prognosis of diffuse large B cell lymphoma (DLBCL). Methods A retrospective study was conducted on formalin-fixed paraffin-embedded tissue blocks of one hundred de novo DLBCL patients diagnosed from 2013 to 2016. PD-L1 expression was defined by a modified Combined-Positive Score (CPS) and their medical records were reviewed to collect their clinical, laboratory and radiological data, treatment, and outcome. Results The included patients were aged from 23 to 85 years and treated by rituximab- cyclophosphamide, doxorubicin, oncovin, prednisone (R-CHOP); 49% were males; 85% of the cases were presented at Ann Arbor stages III, IV; 33% of patients were seropositive for HCV and 87% of cases were presented with intermediate and high IPI. All included cases expressed PD-L1 using modified CPS. 27% of patients showed low PD-L1 expression (≥ 5% to