RESUMO
PURPOSE: To investigate a possible chemorefractoriness mechanism of a Diffuse Large B-Cell Lymphoma (DLBCL) histological subtype, specifically of DLBCL, not otherwise specified (DLBCL, NOS), namely the effect of programmed cell death-1 (PD-1) immunoreceptor signalling, considering that the identification of additional negative prognostic factors can lead to better prognostication and therapeutic approaches. METHODS: We conducted a retrospective study of DLBCL, NOS patients, gathering their clinical features and combining them with PD-1 and its ligand (PD-L1) expression at the time of diagnosis as well as their response to treatment. RESULTS: No statistically significant difference was found when comparing PD-L1 positive to PD-L1 negative patients, while overall survival (OS) and duration of complete response (CR) were better for PD-L1 negative patients but the difference was not statistically significant. CONCLUSIONS: PD-L1 expression was not found to have any prognostic value for our cohort of DLBCL, NOS patients. What is more, the number of PD-1 positive tumour infiltrating lymphocytes was not associated with PD-L1 expression neither on malignant nor on non-malignant cells.
