Grobner et al. reported that mutation frequencies in pediatric cancer types were 14 times lower overall than those in adult cancers.30 Another study found that the majority of PD-L1-amplified tumors (84.8%) had a low to intermediate TMB.29 In our study, all tumors had low TMB, except for one patient with choroid plexus papillary carcinoma who had an intermediate TMB of 8.16 mut/Mb as determined by high-throughput sequencing with 295 cancer gene panels. This evidence concerns the gene CD274 and cancer.