LAUSR

Importance Molecular alterations in lichen sclerosus–associated vulvar squamous cell carcinoma (LS-VSCC) are largely unknown. Objective To determine whether the retinoic acid receptor &bgr; (RAR&bgr;) tumor-suppressor gene is involved in the onset and/or progression of LS-VSCC. Design, Setting, and Participants The case-control study, conducted at University-Hospital of Ferrara, Italy, included 20 LS-VSCC (mean [SD] age, 75 [3] years) and 20 cancer-associated vulvar LS (caVLS; mean [SD] age, 62 [11] years) formalin-fixed embedded tissue specimens, 20 cancer-free vulvar LS (cfVLS), and 20 normal skin fresh specimens from diagnostic biopsies and women surgically treated for nonmalignant skin lesions, respectively. RAR&bgr; gene expression and promoter methylation were investigated in LS-VSCC and caVLS adjacent to VSCC specimens, and in cfVLS and normal skin specimens, as controls, by RT-Q real-time polymerase chain reaction (PCR) analysis, and sequencing of PCR-amplified bisulfite-treated DNA. c-Jun expression, an RAR&bgr; pathway–related gene, was also investigated. Main Outcomes and Measures RAR&bgr; expression, correlation with its promoter methylation and c-Jun expression, and association with onset or progression of LS-VSCC. Results In LS-VSCC, RAR&bgr; messenger RNA was 3.4-, 3.6-, and 4.8-fold lower than in caVLS (P = .001), cfVLS (P = .005), and normal skin (P < .001), respectively. The RAR&bgr; mRNA levels were similar in caVLS, cfVLS, and normal skin. The RAR&bgr; promoter was hypermethylated in 18 (90%) of 20 LS-VSCC, 11 (55%) of 20 cfVLS, 10 (50%) of 20 caVLS, and 5 (25%) of 20 in the normal skin group. The degree of methylation of RAR&bgr; promoter was higher in LS-VSCC, ranging from 5 to 9 (full promoter methylation) CpGs methylated, than in caVLS (P = .02), cfVLS (P = .03), or normal skin (P < .001), which was up to 5 CpGs methylated. Importantly, 0 of 8 LS-VSCC with 5 to 6 CpGs methylated and 5 (63%) of 8 LS-VSCC with 7 to 8 CpGs methylated were from patients with lymph node metastasis at diagnosis, respectively, whereas there were 2 of 2 (100%) LS-VSCC samples with 9 CpG methylated from patients with lymph node metastasis at diagnosis and subsequent recurrence. In LS-VSCC c-Jun mRNA was 4.3-, 1.4-, and 2.6-fold higher than in caVLS (P < .001), cfVLS (P = .001), and normal skin (P < .001), respectively. The expression of c-Jun was similar in caVLS, cfVLS, and normal skin. Conclusions and Relevance Hypermethylation-induced RAR&bgr; down-expression was associated with LS-VSCC and correlates with the upregulation of c-Jun. The degree of methylation of RAR&bgr; promoter increased with the malignancy of LS-VSCC. Therefore, RAR&bgr; gene dysregulation may play a role in progression of LS-VSCC, and RAR&bgr; promoter methylation status may be used as a prognostic marker in clinical treatment of patients with LS-VSCC.