The detection of a TP53 pathogenic variant in the tumor or plasma of patients with early onset diagnosis (< 30 years of age) of TP53 core tumors (breast cancer, soft-tissue sarcoma, osteosarcoma, central nervous system tumor, adrenocortical carcinoma), or other tumors exhibiting an enriched germline conversion rate, such as non-small cell lung cancer or colon cancer, requires further assessment at a Hereditary Cancer Unit (Fig. 1) [15]. The gene discussed is TP53; the disease is osteosarcoma.