Differentiated vulvar intraepithelial neoplasia (dVIN) is the precursor of human papillomavirus (HPV)-independent vulvar squamous cell carcinoma (VSCC). Given the rare incidence of dVIN, limited information on the exact cancer risk is available. We systematically reviewed the primary and recurrent VSCC risk in patients with dVIN, as well as the time to cancer development. A systematic search was performed up to July 2021 according to the PRISMA guidelines. Five reviewers independently screened articles on title, abstract and full text, followed by critical appraisal of selected articles using the Quality in Prognostic Studies (QUIPS) tool. Of the 455 screened articles, 7 were included for analysis. The absolute risk for primary VSCC in dVIN varied between 33 and 86%, with a median time to progression to VSCC of 9–23 months. The risk of developing recurrent VSCC in dVIN associated VSCC was 32–94%, with a median time to recurrence of 13–32 months. In conclusion, patients with dVIN have a high risk of developing primary and recurrent VSCC with a short time to cancer progression. Increased awareness, timely recognition, aggressive treatment and close follow-up of HPV-independent vulvar conditions including dVIN is therefore strongly recommended.

The precursor lesions of vulvar squamous cell carcinoma (VSCC) include human papillomavirus (HPV)‐associated and HPV‐independent squamous neoplasia with a varying cancer risk. Our study aimed to validate the accuracy of previously identified DNA methylation markers for detection of such high‐grade vulvar intraepithelial neoplasia (VIN). A large clinical series of 751 vulvar lesions, originally diagnosed as high‐grade VIN, were reassessed and categorized into HPV‐associated or HPV‐independent vulvar disease categories. Together with 113 healthy vulvar controls, all samples were tested for 12 methylation markers with quantitative multiplex methylation‐specific PCR (qMSP). Performance of individual markers and selection of an optimal marker panel for detection of high‐grade VIN was determined by logistic regression analysis. SST was the best‐performing individual marker (AUC 0.90), detecting 80% of high‐grade VIN cases, with excellent detection of HPV‐independent VIN (95%), known to have the highest cancer risk. Merely 2% of controls tested methylation positive for SST . Selection of a marker panel, including ZNF582 , SST and miR124‐2 , resulted in a comparably high accuracy for detection of high‐grade VIN (AUC 0.89). In conclusion, we clinically validated the accuracy of 12 DNA methylation markers for detection of high‐grade VIN. SST , as a sole marker or in a panel, provides an optimal diagnostic tool to distinguish high‐grade VIN in need of treatment, particularly HPV‐independent VIN, from low‐grade or reactive vulvar lesions. These findings warrant further prognostic validation of methylation biomarkers for cancer risk stratification of patients with VIN.

Objectives: Human papillomavirus (HPV)–independent vulvar intraepithelial neoplasia (VIN) is a rare yet aggressive precursor lesion of vulvar cancer. Our objectives were to estimate its long-term incidence, the risk of recurrent disease and progression to vulvar cancer, and risk factors thereof. Materials and Methods: Patients with HPV-independent VIN between 1991 and 2019 in a selected region were identified from the Dutch Nationwide Pathology Databank (Palga). Data were collected from the pathology reports. Crude and European age-standardized incidence rates were calculated for 10-year periods. Kaplan-Meier analyses were performed to determine the cumulative recurrence and cancer incidence, followed by Cox regression analyses to identify associated risk factors. Results: A total of 114 patients were diagnosed with solitary HPV-independent VIN without prior or concurrent vulvar cancer. The European age-standardized incidence rate increased from 0.09 to 0.69 per 100,000 women-years between 1991–2010 and 2011–2019. A cumulative recurrence and cancer incidence of 29% and 46% were found after 8 and 13 years of follow-up, respectively. Nonradical surgery was identified as the only independent risk factor for recurrent HPV-independent VIN. Risk factors associated with progression to cancer were increasing age and a mutant p53 immunohistochemical staining pattern. Conclusions: The incidence of detected HPV-independent VIN has substantially increased the last decade and the subsequent recurrence and vulvar cancer risks are high. Although HPV-independent VIN may present as a wide morphologic spectrum, surgical treatment should aim for negative resection margins followed by close surveillance, especially for p53 mutant lesions.

Vulvar lichen sclerosus (LS) is an inflammatory dermatosis that can progress to human papillomavirus (HPV)-independent vulvar intraepithelial neoplasia (HPVi VIN) and vulvar squamous cell carcinoma (VSCC). Although LS has a much lower cancer risk compared with HPVi VIN (5% versus 50%, respectively), its incidence is significantly higher. Therefore, there is a clinical need to identify LS patients with an increased cancer risk. Our objective was to study the value of DNA methylation and p53 immunohistochemistry (IHC) as prognostic biomarkers for progression to cancer in patients with LS. Vulvar tissues from 236 patients were selected, including 75 LS and 68 HPVi VIN, both with and without cancer development, 32 VSCC, and 61 healthy vulvar controls. Samples were subjected to p53 IHC and DNA methylation analysis of a 3-gene marker panel containing ZNF582, SST, and miR124-2. Methylation levels and p53 IHC status (mutant or wild-type) were assessed and compared among all disease categories. Odds ratios were determined to identify whether the biomarkers were associated with progression to cancer in patients with LS. The highest methylation levels were found in HPVi VIN and VSCC, followed by LS and healthy vulvar controls. The largest heterogeneity in methylation levels was observed in LS cases. In fact, the 3-marker panel tested positive in 70% of LS, which progressed to VSCC versus only 17% of LS in patients without cancer development (P = .002). Also, mutant p53 IHC was observed more frequently in LS with progression to VSCC compared with nonprogressive LS cases (42% versus 3%, respectively, P = .001). Multivariable analysis identified a mutant p53 status as the only independent risk factor for cancer development in LS (odds ratio: 34.0, 95% CI: 1.4-807.4). In conclusion, DNA methylation testing and p53 IHC show strong potential as prognostic biomarkers for the identification of LS patients at high risk of progression to cancer.

Background: Recently, the immunohistochemical markers cytokeratin 17 (CK17) and SRY-box2 (SOX2) have been evaluated as adjuncts for the diagnosis of high-grade vulvar intraepithelial neoplasia (VIN). In the present study, the aim was to assess CK17 and SOX2 expression in VIN by studying 150 vulvar lesions, originally reported as high-grade VIN and to assess the diagnostic accuracy. Methods: All slides (H&E, p16^INK4a, p53, Ki-67, CK17, and SOX2 stains) were independently assessed by six pathologists and the final diagnosis was reached in consensus meetings, as follows: 46 human papillomavirus (HPV)-independent VIN (including 30 p53 mutant and 16 p53 wild-type lesions), 58 high-grade squamous intraepithelial lesions (HSILs), 4 low-grade SILs (LSILs), 37 non-dysplastic lesions, and 5 lesions where the histology was inconclusive. Results: CK17 positivity was observed in 100% p53 wild-type HPV-independent VIN, compared to 73% p53 mutant HPV-independent VIN, 14% HSILs, 0% LSILs, and 24% non-dysplastic lesions. SOX2 positivity was observed in 13% p53 wild-type HPV-independent VIN, 43% p53 mutant HPV-independent VIN, 2% HSILs, 0% LSILs, and 3% non-dysplastic lesions. The highest diagnostic accuracy (89%) for HPV-independent VIN was obtained when combining p53 and CK17 immunohistochemistry. The addition of SOX2 did not further increase diagnostic accuracy. Conclusion: To conclude, aside from p53, both CK17 and SOX2 can be of value for reaching an accurate diagnosis of HPV-independent VIN.

Background: High-grade vulvar intraepithelial neoplasia (VIN) is the precursor of vulvar cancer. The main variants are human papillomavirus (HPV)-associated high-grade squamous intraepithelial lesion (HSIL) and HPV-independent VIN, often clinically referred to as differentiated VIN (dVIN) and associated with vulvar dermatoses, usually lichen sclerosus. Surgical treatment of high-grade VIN often leads to genital deformity, impaired sexual function and reduced quality of life. To optimize clinical management, accurate biomarkers providing information on the cancer risk of high-grade VIN are needed. Objectives: To investigate the prognostic value of a three-gene methylation marker panel and other potential risk factors for the risk of progression to cancer in patients with HSIL and dVIN. Methods: From a population-based cohort of patients diagnosed with high-grade VIN, patients with a histopathologically confirmed diagnosis of HSIL (n = 578) and dVIN (n = 46) were selected. All lesions were tested by a three-gene methylation panel including the genes ZNF582, SST and miR124-2. The vulvar cancer risk and the prognostic value of methylation status, age, HPV genotype, wild-type vs. mutant p53 immunohistochemistry status and presence of lichen sclerosus were estimated by Kaplan–Meier and Cox regression, respectively. Results: Vulvar cancer developed in 26 of 578 patients with HSIL (4.5%) and in 21 of 46 with dVIN (46%) within 5 years. In HSIL, positive methylation status was identified as the only prognostic factor for vulvar cancer development [hazard ratio (HR) 4.87, 95% confidence interval (CI) 1.20–21.45]. The prognostic value of methylation remained present when selecting patients who did not receive radical surgical excision as their primary treatment. In this group, the 5-year cancer risk was 7.7% in methylation-positive HSIL and 1.4% in methylation-negative HSIL (P = 0.008). In dVIN, mutant p53 status was the sole prognostic risk factor for progression to cancer (HR 7.67, 95% CI 1.78–33.08). Conclusions: Despite wide CIs, the three-gene methylation test serves as a promising prognostic tool for cancer risk stratification in patients with vulvar HSIL. Patients with methylation-negative HSIL carry a low cancer risk, allowing for more conservative management strategies. This approach may help avoid overtreatment, reducing morbidity and improving quality of life.