Rotondo JC, et al. - Authors ascertained if the retinoic acid receptor β (RARβ) tumor-suppressor gene is involved in the onset and/or progression of lichen sclerosus–associated vulvar squamous cell carcinoma (LS-VSCC). Results demonstrated an association of hypermethylation-induced RARβ down-expression with LS-VSCC and its correlates with the upregulation of c-Jun. Experts noted an increase in the degree of methylation of RARβ promoter with the malignancy of LS-VSCC. Hence, a role in the progression of LS-VSCC could be played by RARβ gene dysregulation. In clinical treatment of patients with LS-VSCC, RARβ promoter methylation status could be used as a prognostic marker.

Methods

• In this case-control study conducted at University-Hospital of Ferrara, Italy, experts 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.
• They gauged the RARβ gene expression and promoter methylation 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.
• They also investigated the c-Jun expression, which is an RARβ pathway–related gene.
• RARβ expression, correlation with its promoter methylation, and c-Jun expression, and association with onset or progression of LS-VSCC were the main outcomes and measures.

Results

• As per data, in LS-VSCC, RARβ 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.
• Findings suggested that in caVLS, cfVLS, and normal skin the RARβ mRNA levels were similar.
• Results demonstrated that the RARβ 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.
• Researchers noted that the in LS-VSCC degree of methylation of RARβ promoter was higher, 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.
• They noted that 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.
• c-Jun mRNA was 4.3-, 1.4-, and 2.6-fold higher in LS-VSCC vs caVLS (P < .001), cfVLS (P=.001), and normal skin (P < .001), respectively.
• Similar expression of c-Jun was noted in caVLS, cfVLS, and normal skin.