CDKN2A/CDK4 status in Brazilian patients meeting clinical criteria for hereditary melanoma: a cross-sectional descriptive trial.

Background: Melanoma is the most lethal skin cancer, and its incidence has increased worldwide. About 10% of cases are classified as hereditary melanoma (HM). CDKN2A and CDK4 are the major high-risk genes. Families are also more prone to develop pancreatic cancer, and different forms of oncological surveillance are recommended.

Objectives: Describe the prevalence of CDKN2A/CDK4 germline mutations in melanoma-prone patients and their phenotypic and histopathological features.

Methods: A total of 69 patients meeting the clinical criteria for HM were included in this cross-sectional descriptive study. Amplification by PCR and genomic sequencing were used. The variants were classified according to American College of Medical Genetics (ACMG) criteria.

Results: The mean age at first diagnosis of melanoma was 44.8 years (SD ± 17.83). Most patients had phototype II (44.9%), more than 50 melanocytic nevi (76.8%), atypical nevus syndrome (72.5%), history of sunburn (76.8%), and multiple primary melanomas without a family history of this tumor (74.3%). Two hundred melanomas were observed. Most tumors had a Breslow index ≤1.0 mm (84.5%), location in the trunk (60.5%), and superficial spreading histological subtype (22.5%). Four variants were found in CDKN2A exons in seven patients (c.305C>A, c.26T>A, c.361G>A e c.442G>A), two variants in the 5'UTR region in five patients (c.-25C>T and c.-33G>C), and two variants in the 3'UTR region in 21 patients (c.*29C>G and c.*69C>T). One likely pathogenic variant (c.305C>A) was identified in one patient (1.4%). No variant was found in CDK4.

Conclusion: The prevalence of CDKN2A mutations was 1.4% in Brazilian patients meeting clinical criteria for HM.