On the Hunt for the Missed Genetic Causes of Multiple Primary Tumors.

Improved cancer screening and treatment programs have led to an increased survivorship of patients with cancer, but consequently also to the rise in number of individuals with multiple primary tumors (MPT). Germline testing is the first approach investigating the cause of MPT, as a positive result provides a diagnosis and proper clinical management to the affected individual and their family. Negative or inconclusive genetic results could suggest non-genetic causes, but are negative genetic results truly negative? Herein, we discuss the potential sources of missed genetic causes and highlight the trove of knowledge MPT can provide. See related article by Borja et al., p. 209.

Segregation, immunohistochemical, molecular and functional analyses classify a novel missense variant in fumarate hydratase (FH) as pathogenic.

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an autosomal dominant cancer predisposition syndrome characterized by cutaneous leiomyomas, uterine leiomyomas, and aggressive renal cancer. Germline variants in the fumarate hydratase (FH) gene predispose to HLRCC. Identifying germline pathogenic FH variants enables lifetime renal cancer screening and genetic testing for family members. In this report, we present a FH missense variant (c.1039T>C (p.S347P)), initially classified as a variant of uncertain significance. Clinical assessment, histopathological findings, molecular genetic studies, and enzymatic activity studies support the re-classification of the FH c.1039T>C variant to "pathogenic" based on ACMG/AMP criteria. Further insights into pathological recognition of FH-deficient renal cancer are discussed and should be recognized. This study has shown how (a) detailed multi-disciplinary analyses of a single variant can reclassify rare missense variants in FH and (b) careful pathological review of renal cancers is obligatory when HLRCC is suspected.