Background: Cancer predisposition syndromes (CPS) are caused by germline pathogenic variants that put an individual at increased risk of developing cancer throughout their lifetime. It is estimated that approximately 10-15% of children with cancer have an underlying CPS. Although research has investigated the clinical utility of genetic testing for children diagnosed with cancer, this study aimed to gain a deeper understanding of parental attitudes toward genetic testing in this population. Procedure: Attitudes toward genetic counseling and testing among parents of children diagnosed with cancer were solicited through questionnaires distributed to a pediatric cancer clinic and online support groups. Quantitative data were analyzed using descriptive statistics and chi-square tests for association.

Background The association of childhood cancer with Lynch syndrome is not established compared with the significant pediatric cancer risk in recessive constitutional mismatch repair deficiency syndrome (CMMRD). Procedure We describe the clinical features, germline analysis, and tumor genomic profiling of patients with Lynch syndrome among patients enrolled in pediatric cancer genomic studies. Results There were six of 773 (0.8%) pediatric patients with solid tumors identified with Lynch syndrome, defined as a germline heterozygous pathogenic variant in one of the mismatch repair (MMR) genes (three with MSH6, two with MLH1, and one with MSH2). Tumor analysis demonstrated evidence for somatic second hits and/or increased tumor mutation burden in three of four patients with available tumor with potential implications for therapy and identification of at‐risk family members. Only one patient met current guidelines for pediatric cancer genetics evaluation at the time of tumor diagnosis. Conclusion Approximately 1% of children with cancer have Lynch syndrome, which is missed with current referral guidelines, suggesting the importance of adding MMR genes to tumor and hereditary pediatric cancer panels. Tumor analysis may provide the first suggestion of an underlying cancer predisposition syndrome and is useful in distinguishing between Lynch syndrome and CMMRD.