By testing ancillary materials, multiple germ layers and/or clinical data to interrogate germline status on the 20 carriers, 11 (55%) patients were confirmed to carry a germline mutation, 2 (10%) patients were confirmed to have de novo germline mutations (Fig. 1), and 4 (20%) were presumed to have de novo germline mutations based on the negative test result of TP53 mutation among multiple family members and/or lack of cancer history in families. Here, TP53 is linked to cancer.