Retrospective cohort study of profiling tumor-infiltrating immune cells in pediatric medulloblastoma

A multicenter retrospective cohort study in China investigated the prognostic value of various tumor-infiltrating immune cells in pediatric medulloblastoma (MB). Densities of T cells, B cells, NK cells, macrophages, and immune checkpoints in tumor samples of 249 pediatric patients with primary MB were assessed with multiplex immunofluorescent staining. Significant differences in the immune microenvironment among molecular groups of MB and their prognostic implications were observed. CD4+ T cell infiltration was positively correlated with improved overall survival (low versus high HR 2.19; 95% CI 1.20-4.02), while M2 macrophages (0.50; 0.25-1.00), NK cells (0.40; 0.21-0.79), and B cells (0.51; 0.29-0.90) were associated with poorer progression-free survival. Infiltration of B cells (low versus high HR 0.50; 95% CI 0.27-0.94) was associated with poorer overall survival. In multivariate Cox regression analysis, B cells were identified as independent negative prognosticators for overall survival (high versus low HR 2.21; 95% CI 1.34-3.65) and progression-free survival (2.15; 1.28-3.61). The authors conclude that this study provides a comprehensive characterization of the prognostic value of tumor-infiltrating immune cells in pediatric medulloblastoma (graphical abstract).