Abstract B37: Clinical relevance of tumor-infiltrating immune cells in neuroblastoma

The presence of tumor-infiltrating T cells is crucial for the development of immunotherapies and the prediction of clinical response for many human cancers. Recently, we have shown that tumor-infiltrating T cells have a prognostic value greater than, and independent of, the criteria currently used to stage neuroblastoma, the most common pediatric extra-cranial solid tumor accounting for 15% of childhood cancer-related death. We demonstrated that expression of PD-L1 in tumor cells is inversely correlated with that of HLA class I, and that when combined they represent a promising prognostic biomarker in neuroblastoma. To further dissect the immune heterogeneity of neuroblastoma microenviroment, we evaluated the density of infiltrating dendritic cells (iDC), which are crucial for drug-induced anticancer immune response, in the same cohort of NB samples characterized for type, density, and composition of tumor T lymphocytes and expression of tumor PD-L1 and HLA class I. As for T cells, high density of iDCs was correlated with the presence of infiltrating T cells, expression of tumor HLA class I and favorable clinical outcome, suggesting that iDCs may be critical for robust tumor control by improving prediction of patient survival. Citation Format: Ombretta Melaiu, Renata Boldrini, Marco Chierici, Cesare Furlanello, Doriana Fruci. Clinical relevance of tumor-infiltrating immune cells in neuroblastoma [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr B37.