Pooled results showed that tumor cell PD-L1 expression is associated with poor overall survival (OS) (HR = 2.128, 95% CI: 1.341–3.378, P = 0.001), the non-germinal center B-cell-like subtype (OR = 2.891, 95% CI: 2.087–4.003, P < 0.000), high international prognostic index score (3–5) (OR = 1.552, 95% CI: 1.111–2.169, P = 0.010), B symptoms (OR = 1.495, 95% Cl: 1.109–2.015, P = 0.008), positive MUM1 expression (OR = 3.365, 95% Cl: 1.578–7.175, P = 0.002) and negative BCL6 expression (OR = 0.414, 95% Cl: 0.217–0.792, P = 0.008). The gene discussed is BCL6; the disease is neoplasm.