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 of Verona, Italy, from 2000 to 2022, presenting at least one of the followings: multiple melanomas (≥ 3); personal/family history of pancreatic cancer (PC) (up to 2(nd)-degree relatives); ≥ 2 1(st)-degree relatives with melanoma; ≥ 1 1(st)-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 1320 patients (2.7%) underwent genetic testing. Four patients (11.4%) harbored a PV in a melanoma-predisposing gene, three in CDKN2A (8.6%), and one 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.