Potential role of the PD-L1 expression and tumor-infiltrating lymphocytes on neuroblastoma

Purpose The programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway has garnered much attention for its roles in clinical oncology. The aim of this study was to examine the clinical impact of the PD-L1 expression and tumor-infiltrating lymphocytes (TILs) on neuroblastoma. Methods We evaluated the PD-L1 expression and TIL status in 31 patients with neuroblastoma who underwent a biopsy or resection by an immunohistochemical analysis. Furthermore, we performed the serial analysis of the PD-L1 status before and after chemotherapy in 15 patients. Results Among the 31 cases, 11 (35%) showed a positive PD-L1 expression. The survival analysis showed a trend toward an association between PD-L1 positivity and a decreased overall survival. PD-L1 positivity tended to be associated with higher levels of tumor markers. In the serial analysis of the PD-L1 status, positivity was noted in 8 of 15 patients before chemotherapy and 6 after chemotherapy. Notably, all four patients with a positive PD-L1 status both before and after chemotherapy had recurrence, and 3 of them died during the follow-up period. Conclusion Our findings suggest that the PD-L1 tumor expression might be a good biomarker for the treatment of neuroblastoma patients, especially for advanced neuroblastoma.