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Brief Report
August 2016

Hypermethylation-Induced Inactivation of the IRF6 Gene as a Possible Early Event in Progression of Vulvar Squamous Cell Carcinoma Associated With Lichen Sclerosus

Author Affiliations
  • 1Section of Pathology, Oncology, and Experimental Biology, Department of Morphology, Surgery, and Experimental Medicine, University of Ferrara, Ferrara, Italy
  • 2Section of Dermatology and Infectious Diseases, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
  • 3Department of Medical Sciences, University of Ferrara, Ferrara, Italy
  • 4Section of Anatomic Pathology, Department of Morphology, Surgery, and Experimental Medicine, University of Ferrara and S. Anna University Hospital, Ferrara, Italy
JAMA Dermatol. 2016;152(8):928-933. doi:10.1001/jamadermatol.2016.1336

Importance  The molecular mechanism leading to the development of vulvar squamous cell carcinoma (VSCC) from vulvar lichen sclerosus (VLS) is unknown.

Objective  To assess the possible involvement of the IRF6 tumor-suppressor gene in the development of VSCC from VLS.

Design  In laboratories at the University of Ferrara, Ferrara, Italy, IRF6 gene expression and promoter methylation were investigated in paraffin-embedded VSCC and adjacent vulvar intraepithelial neoplasia (VIN) and VLS specimens, in cancer-free VLS (cfVLS) specimens, and in healthy skin specimens by reverse transcriptase–quantitative polymerase chain reaction (RT-qPCR) analysis and by sequencing of PCR-amplified bisulfite-treated DNA. Methylation-induced dysregulation was assessed by expression of p63, the IRF6-transactivator gene.

Main Outcomes and Measures  IRF6 expression, correlation with promoter methylation and p63 expression, and association with development of VSCC from VLS.

Results  Specimens from 60 participating women (1 specimen from each) were analyzed for the study (mean [SD] age, 66.3 [12.1] years): 20 paraffin-embedded specimens of VSCC (patient age, 75.3 [8.3] years) with adjacent VLS lesions, in 5 of which VIN preneoplastic tissue was also present (patient age, 64.3 [15.3] years); 20 cfVLS specimens (patient age, 62.1 [11.4] years) obtained from diagnostic biopsies; and 20 normal skin specimens from noncancer surgical patients (patient age, 61.4 [9.1] years). IRF6 messenger RNA was found to be reduced 4.5-, 2.9-, 6.6-, and 2.2-fold in VLS, VIN, VSCC, and cfVLS specimens, respectively, compared with controls, although p63 was still expressed in all specimens. IRF6 promoter was hypermethylated in 9 (45%) of 20 VLS specimens, 1 (20%) of 5 VIN specimens, 16 (80%) of 20 VSCC specimens, 2 (10%) of 20 cfVLS specimens, and 0 normal skin specimens.

Conclusions and Relevance  IRF6 dysregulation may be involved in the development of VSCC from VLS. Methylation of the IRF6 promoter may be a marker of cancer risk in patients with VLS.

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