EBV Positivity and Programmed Death-ligand 1 Expression in Diffuse Large B-cell Lymphoma: A Systematic Review.

BACKGROUND/AIM Diffuse large B-cell lymphoma (DLBCL) is the most common form of non-Hodgkin lymphoma. A systematic review to evaluate the association between Epstein-Barr Virus (EBV) and programmed death ligand-1 (PD-L1) in DLBCL biopsy was conducted. MATERIALS AND METHODS Only studies comparing EBV+ and EBV- groups were eligible following database search. Prevalence ratios were calculated for results comparison. The EBV impact on PD-L1 positivity in tumour cells and its microenvironment was analysed. RESULTS With 270 records screened, eleven cross-sectional studies were identified for final review. Eight studies investigated PD-L1 expression in tumour cells and found an EBV trend unlikely, while four studies found an increase in its expression in the tumour microenvironment. Nine studies showed that EBV+ cases were more commonly of non-germinal centre B-cell origin. Four studies examined genetic aberrations, but no definite consensus was reached. CONCLUSION A non-EBV related mechanism is likely related to increased PD-L1 expression, with relevance to the cell of origin.