Association of Retinoic Acid Receptor beta Gene With Onset and Progression of Lichen Sclerosus-Associated Vulvar Squamous Cell Carcinoma

作者：Rotondo John Charles; Borghi Alessandro; Selvatici Rita; Mazzoni Elisa; Bononi Ilaria; Corazza Monica; Kussini Jacqueline; Montinari Elena; Gafa Roberta; Tognon Mauro; Martini Fernanda^*

来源：JAMA Dermatology, 2018, 154(7): 819-823.

DOI：10.1001/jamadermatol.2018.1373

carcinoma (LS-VSCC) are largely unknown. OBJECTIVE To determine whether the retinoic acid receptor beta (RAR beta) 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 beta 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 beta pathway-related gene, was also investigated.
MAIN OUTCOMES AND MEASURES RAR beta expression, correlation with its promoter methylation and c-Jun expression, and association with onset or progression of LS-VSCC.
RESULTS In LS-VSCC, RAR beta 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 beta mRNA levels were similar in caVLS, cfVLS, and normal skin. The RAR beta 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 beta 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 beta down-expression was associated with LS-VSCC and correlates with the upregulation of c-Jun. The degree of methylation of RAR beta promoter increased with the malignancy of LS-VSCC. Therefore, RAR beta gene dysregulation may play a role in progression of LS-VSCC, and RAR beta promoter methylation status may be used as a prognostic marker in clinical treatment of patients with LS-VSCC.

• 出版日期2018-7