PD-L1 and PD-L2 Mutations in Pediatric Hodgkin Lymphoma: Do They Have Any Prognostic Significance?

Expression Profile of Selected Antitumor Immune Response Genes in Pediatric Classic Hodgkin Lymphoma

Classic Hodgkin lymphoma (cHL) is one of the most common pediatric solid tumors and is responsible for cancer-related deaths in children. Therefore, to modulate the active antitumor T-cell immune response in cHL can be a treatment strategy. In the present study, we aimed to investigate the expression profiles of selected antitumor immune response genes in pediatric cHL and their relationships with clinical and prognostic parameters to determine their significance in precision medicine. Thirty-nine pediatric nodal cHL patients were enrolled in the study. We analyzed mRNA expression of selected immune response regulatory genes such as PD-L1, CSF2, CTLA4, CXCL5, IDO1, CXCL8, MIF, NOS2, PDCD1, PTGS2, and TGFβ1 using real-time quantitative polymerase chain reaction. Only PD-L1 overexpression was statistically related to bulky disease, advanced tumor stage, and high-risk disease category and seen significantly in Epstein-Barr virus-negative pediatric cHL. No expression profiles were correlated with relapse or survival. We conclude that PD-L1 overexpression in pediatric cHL cases is a strong predictor of high-risk categorization. In addition to being a prognostic biomarker, PD-L1 blockade is also a druggable marker for the targeted therapy in Epstein-Barr virus-negative pediatric Hodgkin lymphoma.

Combination Therapy With Anti-PD-1 or PD-1 Antibody Alone in Asian Pediatric Patients With Relapsed or Refractory Cancer

There is limited experience of PD-1 antibody combined with other therapies in children. We aimed to explore the antitumor activity and safety of PD-1 antibody monotherapy or combination with other regimens in relapsed or refractory pediatric cancer. This is a retrospective-case study conducted in two Chinese expert centers. The primary objective of this study was to describe the overall response rate (ORR) and disease control rate (DCR). Secondary objectives included characterizing toxicities. Of the 22 pediatric patients with cancer who received PD-1 inhibitors, the median follow-up for all patients after the commencement of PD-1 therapy with or without other regimens was 12.3 months (0 - 43 months). PD-1 antibody monotherapy demonstrated antitumor activity in a population of pediatric patients with Hodgkin lymphoma (HL), with an objective response rate (ORR) and disease control rate (DCR) of 83.3% (3CR and 2PR) and 100%, respectively. However, no objective response was observed in patients with melanoma or Burkitt lymphoma evaluated in this study. We reviewed responses for patients with chemotherapy, decitabine or everolimus combination therapies with PD-1 antibodies, and found that PD-1 antibody combined with decitabine showed potential efficacy in pediatric patients with advanced embryonal rhabdomyosarcoma and lymphoepitheliomatoid-like carcinoma. There were no severe treatment-related adverse events (TRAEs) directly attributed to PD-1 antibody monotherapy in Asian pediatric patients with lower incidence of hematologic toxicity and nonhematologic toxicity. The Grade ≥3 TRAEs were attributed to the combination chemotherapy.