Genomic biomarkers for immunotherapy response in pediatric solid tumors

Immunotherapy is an increasingly popular treatment strategy offering hope for many cancers. The FDA (Food and Drug Administration) has just approved the use of immune checkpoint inhibitors for treating malignancies in both adults and children. Immune checkpoint inhibitors have been more successful in treating adult cancers than in pediatric cancers. Adult tumors have a higher tumor mutation burden (TMB) than pediatric tumors. The level of microsatellite instability (MSI) in adult tumors is greater than in pediatric solid tumors due to DNA-mismatch deficiency. TMB in tumors correlates with MSI. TMB and MSI analysis are genomic biomarkers for immune checkpoint blockade response in tumors. TMB and MSI analyses have been used in clinical practice to predict which patients are candidates for immunotherapy. This review evaluates the use of TMB and MSI analysis to predict the immunotherapy response of pediatric tumors.