title: LINE-1 hypomethylation and mutational status in cutaneous melanomas.
abstract: Epigenetic dysregulation is an important emerging hallmark of cutaneous melanoma development. The global loss of DNA methylation in gene-poor regions and transposable DNA elements of cancer cells contributes to increased genomic instability. Long interspersed element-1 (LINE-1) sequences are the most abundant repetitive sequence of the genome and can be evaluated as a surrogate marker of the global level of DNA methylation. In this work, LINE-1 methylation levels were evaluated in cutaneous melanomas and normal melanocyte primary cell cultures to investigate their possible association with both distinct clinicopathological characteristics and tumor mutational profile. A set of driver mutations frequently identified in cutaneous melanoma was assessed by sequencing (actionable mutations in BRAF, NRAS, and KIT genes, and mutations affecting the TER T promoter) or multiplex ligation-dependent probe amplification (MLPA) (CDKN2A deletions). Pyrosequencing was performed to investigate the methylation level of LINE-1 and CDKN2A promoter sequences. The qualitative analysis showed a trend toward an association between LINE-1 hypomethylation and CDKN2A inactivation (p=0.05). In a quantitative approach, primary tumors, mainly the thicker ones (>4 mm), exhibited a trend toward LINE-1 hypomethylation when compared with control melanocytes. To date, this is the first study reporting in cutaneous melanomas a possible link between the dysregulation of LINE-1 methylation and the presence of driver mutations.
authors.affiliation: International Research Center, AC Camargo Cancer Center, São Paulo, Brazil.
authors.forename: Dimitrius T
authors.initials: DT
authors.lastname: Pramio
authors.affiliation: Clinical Chemistry and Toxicology Department, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Paula C
authors.initials: PC
authors.lastname: Pennacchi
authors.affiliation: Clinical Chemistry and Toxicology Department, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Silvya S
authors.initials: SS
authors.lastname: Maria-Engler
authors.affiliation: Department of Anatomic Pathology, AC Camargo Cancer Center, São Paulo, Brazil.
authors.forename: Antônio H J F M
authors.initials: AH
authors.lastname: Campos
authors.affiliation: Skin Cancer Department, AC Camargo Cancer Center, São Paulo, Brazil.
authors.forename: João P
authors.initials: JP
authors.lastname: Duprat
authors.affiliation: International Research Center, AC Camargo Cancer Center, São Paulo, Brazil.
authors.forename: Dirce M
authors.initials: DM
authors.lastname: Carraro
authors.affiliation: Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Ana C V
authors.initials: AC
authors.lastname: Krepischi
mesh_terms: D019175:DNA Methylation / Q000235:genetics*; D004252:DNA Mutational Analysis; D006801:Humans; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D008545:Melanoma / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D012878:Skin Neoplasms; D000096142:Cutaneous Malignant Melanoma
keywords: Biomedical Research; Cancer; Genotype