Philip J. Lupo

Adult-Onset Cancer Predisposition Syndromes in Children and Adolescents—To Test or not to Test?

Abstract With the increasing use of comprehensive germline genetic testing of children and adolescents with cancer, it has become evident that pathogenic variants (PV) in adult-onset cancer predisposition genes (aoCPG) underlying adult-onset cancer predisposition syndromes, such as Lynch syndrome or hereditary breast and ovarian cancer, are enriched and reported in 1% to 2% of children and adolescents with cancer. However, the causal relationship between PVs in aoCPGs and childhood cancer is still under investigation. The best-studied examples include heterozygous PVs in mismatch repair genes associated with Lynch syndrome in children with mismatch repair deficient high-grade glioma, heterozygous PVs in BARD1 in childhood neuroblastoma, and heterozygous PVs in BRCA2 in children with rhabdomyosarcoma. The low penetrance for pediatric cancers is considered to result from a combination of the low baseline risk of cancer in childhood and the report of only a modest relative risk of disease in childhood. Therefore, we do not advise that healthy children empirically be tested for PVs in an aoCPG before adulthood outside a research study. However, germline panel testing is increasingly being performed in children and adolescents with cancer, and exome and genome sequencing may be offered more commonly in this population in the future. The precise pediatric cancer risks and spectra associated with PVs in aoCPGs, underlying cellular mechanisms and somatic mutational signatures, as well as treatment response, second neoplasm risks, and psycho-oncological aspects require further research.

Update on Cancer Screening in Children with Syndromes of Bone Lesions, Hereditary Leiomyomatosis and Renal Cell Carcinoma Syndrome, and Other Rare Syndromes

Abstract The management of children with syndromes associated with an increased risk of benign and malignant neoplasms is a complex challenge for health care professionals. The 2023 American Association for Cancer Research Childhood Cancer Predisposition Workshop provided updated consensus guidelines on cancer surveillance in these syndromes, aiming to improve early detection and intervention and reduce morbidity associated with such neoplasms. In this article, we review several of the rare conditions discussed in this workshop. Ollier disease and Maffucci syndrome are enchondromatoses (disorders featuring benign bone lesions) with up to 50% risk of malignancy, including chondrosarcoma. These patients require surveillance with baseline whole-body MRI and routine monitoring of potential malignant transformation of bony lesions. Hereditary multiple osteochondromas carry a lower risk of chondrosarcoma (<6%) but still require lifelong surveillance and baseline imaging. Related syndromes of benign bone lesions are also described. Hereditary leiomyomatosis and renal cell carcinoma syndrome, associated with fumarate hydratase pathogenic variants, is discussed in detail. Surveillance for renal cell carcinoma in pediatric age is recommended, as well as prompt intervention when a lesion is detected. Schinzel–Giedion syndrome and Rubinstein–Taybi syndrome are described for their associated malignancies and other complications, as well as expert consensus on the need for childhood cancer surveillance. Clinical recommendations, including imaging modalities and frequency of screenings, are proposed and are tailored to each syndrome's age-specific tumor risk profile. In all syndromes, patients and their families should be educated about the potential malignancy risk and advised to seek medical care for rapid growth of a mass, persistent pain, or other unexplained symptoms.