What is Known: • The proportion of cancers in children attributable to an underlying genetic syndrome or inherited susceptibility is unclear. • Pediatricians consider children diagnosed with cancer for inherited cancer susceptibility according to well-established clinical criteria.

What is New: • Genetic testing of tumor samples can incidentally uncover an underlying cancer susceptibility syndrome. • Findings in tumor genetics can be indicative that the tumor arose on the basis of the child’s germline alteration, (a) chromothripsis and (b) a high total number of mutational events which exceeds that of other samples of the same tumor type.