PB1783 PROGRAMMED CELL DEATH‐1 AND PROGRAMMED CELL DEATH LIGANDS EXPRESSION IN NODAL PERIPHERAL T‐CELL LYMPHOMA

Abstract

Background:Program cell death‐1/Program cell death ligands (PD‐1/PD‐Ls) is an important element of immune response regulation in human. Activation of PD‐1/PD‐Ls results in an inhibition of cellular mediated immune response. Several cancers including lymphoma exhibit abnormal PD‐1/PD‐Ls expression which may contribute to treatment failure and worse outcome. However, data of PD‐1/PD‐Ls expression in peripheral T cell lymphomas (PTCLs) has been sparsely described. Herein, we described expression patterns of PD‐1/PD‐Ls in PTCLs and explored their correlation with clinical parameters.Aims:To describe expression features of PD‐1/PD‐Ls in PTCLs and explore their correlation with clinical characteristics and outcomesMethods:We included 51 adult PTCLs diagnosed and followed up at King Chulalongkorn Memorial Hospital between 2550 and 2561. Medical records were abstracted for detailed clinical data. Paraffin embedded tissue archives were further stained for PD‐1, PD‐L1 and PD‐L2 which were independently interpreted for expression level and intensity by two hematopathologists. Membranous staining more than 5% was used as a positive cut off criteria. Correlation with clinical parameters was then analyzed.Results:Of 51 PTCLs, PD‐1, PD‐L1 and PD‐L2 were seen in 27.5%, 49.0% and 68.6% of PTCLs respectively. The expression patterns and frequency of PD‐1/PD‐Ls have varied among different histologic subtypes. There was no significant difference in baseline clinical characteristics between PD‐Ls expression status. With median follow up duration of 15 months, the 1‐year event free survival (EFS) and overall survival (OS) were 43.9 % and 61.6% respectively. Neither EFS nor OS was different among PD‐L1 or PD‐L2 expression cohort (1‐year EFS 39.3% in negative PD‐L1 lymphoma vs 46.9% in positive PD‐L1 lymphoma, 1‐year EFS 40.5% in negative PD‐L2 lymphoma vs 49.5% in positive PD‐L2 lymphoma) (1‐year OS 55.2% in PD‐L1 negative lymphoma vs 59.5% in PD‐L1 positive lymphoma, 1‐year OS 57.7% in PD‐L2 negative lymphoma vs 56.8% in PD‐L2 positive lymphoma). Univariate cox regression analysis showed that performance status was the only prognostic factor for survivals. PD‐1 and PD‐Ls expression status, either on lymphoma cells or non‐tumor stroma, were not predictive factors for treatment outcomes.Summary/Conclusion:Aberration expression of PD‐1/PD‐Ls could be seen in PTCLs and was varied among histologic subtypes. Clinical characteristics, treatment response and survivals were not statistically different among PD‐1 and PD‐Ls expression patterns.image