Prevalence of CDKN2A, CDK4, POT1, BAP1, MITF, ATM, and TERT Pathogenic Variants in a Single-Center Retrospective Series of Patients With Melanoma and Personal or Family History Suggestive of Genetic Predisposition

Abstract

Introduction: Approximately 20%-45% of familial melanoma (FM) cases are associated with genetic predisposition. Objectives: This single-center retrospective study aimed to assess the frequency of pathogenic variants (PV) in the main melanoma-predisposing genes in patients with cutaneous melanoma and investigate the clinical predictors of genetic predisposition. Methods: Patients included were those diagnosed with cutaneous melanoma at the Dermatology Unit of the University Hospital, Verona, Italy, from 2000 to 2022, presenting at least one of the following: multiple melanomas (≥3); personal/family history of pancreatic cancer (PC) (up to second-degree relatives); ≥2 first-degree relatives with melanoma; ≥1 first-degree relatives with early onset (<45 years) melanoma and tested for CDKN2A, CDK4, POT1, BAP1, MITF, ATM, and TERT. Results: During the study period, 35 out of 1,320 patients (2.7%) underwent genetic testing. Four patients (11.4%) harbored a PV in a melanoma-predisposing gene, 3 in CDKN2A (8.6%), and 1 in MITF (2.9%). Variants currently classified as being of unknown clinical significance (VUS) were detected in CDKN2A (n=1), MITF (n=1), and ATM (n=2). Family history of PC and ≥5 melanomas, personal history of ≥50 nevi, and ≥4 melanomas were significantly associated with PV in tested genes (P<0.05). Conclusions: The prevalence of PV in predisposing genes in FM was lower than previously reported in Italian registries. Possible reasons include deleterious variants in untested intermediate-/low-penetrance genes or yet-to-be-discovered high-penetrance genes and environmental risk factors. A family history of PC, a high number of nevi and melanomas predict a monogenic predisposition to melanoma.