Abstract
Introduction: Programmed death 1 (PD-1) is a co-receptor which is
located at the surface of cells like natural killer, monocytes, T and B
cells. It has two ligands including programmed death ligand-1 (PD-L1)
and ligand-2 (PD-L2). T cell functions are inhibited by activation of
PD-1/PD-L1 pathway and this pathway is used by viruses and some tumor
cells in order to escape from immune eradication. In our study we
evaluated PD-L1 expression in the tissue specimens of patients with
Wilms tumor, neuroblastoma and other renal tumors. Material and Methods:
Totally 60 patients who were followed up at Gazi University Hospital
with the diagnosis of neuroblastoma, Wilms tumor and other renal tumors
were included. PD-L1 expression was examined in tumor samples of the
patients. Results: Positive staining with PD-L1 was detected only in two
male patients. Both of them had neuroblastoma and advanced stage
disease. None of the patients with Wilms tumor and other renal tumors
had positive PD-L1 staining. Conclusion: Unlike adult tumors; PD-L1
expression is not common in childhood tumors due to differences in
immune system between children and adults. Further studies are needed to
establish the importance and effects of PD-1/PD-L1 pathway in pediatric
tumors.