TY - JOUR T1 - PD-1 and PD-L1 expression in thymic epithelial tumours and non-neoplastic thymus JF - Journal of Clinical Pathology JO - J Clin Pathol DO - 10.1136/jclinpath-2017-204788 SP - jclinpath-2017-204788 AU - Emine Kilic Bagir AU - Arbil Acikalin AU - Alper Avci AU - Derya Gumurdulu AU - Semra Paydas Y1 - 2018/02/08 UR - http://jcp.bmj.com/content/early/2018/02/08/jclinpath-2017-204788.abstract N2 - Aims We explored the relationships between programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) expression and the pathological and clinical features of thymic epithelial tumours and thymic hyperplasia.Methods We evaluated PD-1 and PDL-1 expressions within epithelial and microenvironmental components in thymic epithelial tumours (n=44) and thymic hyperplasias (n=8), immunohistochemically. We compared the results with demographic, clinical and histopathological features of the cases.Results We found 48% epithelial expression and 82.7% microenvironment expression for PD-1 and 11.5% epithelial expression and 34.6% microenvironment expression for PD-L1. There was no PD-1 expression, in either the epithelial or microenvironment, in the thymic hyperplasia group. PD-1 and PD-L1 positivity was more significant in thymic epithelial tumours than thymic hyperplasia. Patients with PD-1-positive microenvironments exhibited significantly shorter mean estimated survival time than their negative counterparts.Conclusion These findings suggest that anti-PD-1 and anti-PD-L1 therapies may benefit patients due to high release of PD-1 and PD-L1 in thymic epithelial tumours. ER -