Exploring Differentially Methylated Genes in Vulvar Squamous Cell Carcinoma

Non-invasive diagnosis of vulvar dysplasia using cervical methylation markers-a case control study

BACKGROUND

Diagnostic screenings for vulvar squamous intraepithelial lesions (VSIL) are limited and without information on disease trends. A panel of six methylation markers (ASTN1, DLX1, ITGA4, RXFP3, SOX17, ZNF671; GynTect® assay) has shown promise in diagnosing cervical intraepithelial neoplasia (CIN). Given the similarities between the carcinogenesis of cervix and vulva, this study aimed to investigate the suitability of these markers for diagnosing vulvar lesions.

METHODS

One hundred twenty-one vulvar FFPE samples and 237 vulvar cell smears with different VSIL grades, HPV status, and with or without lichen sclerosus and planus were tested. Additionally, dysplasia-free vulvar cell smears from patients with cervical dysplasia were analyzed. The expression of DNA methyltransferases (DNMTs) in the FFPE samples was measured.

RESULTS

The markers demonstrated high specificity in vulvar smears, with sole 5.45% of dysplasia-free smears testing positive. Yet, 75.00% of vulvar carcinoma smears appear positive in the methylation kit, similar to VHSIL (VIN III) smears with 77.78%. In FFPE samples, dysplasia-free samples from the tumor microenvironment of high-grade vulvar neoplasia showed 43.75% positivity. The positivity rates for VSIL and carcinoma samples were 76.92%, 64.71%, 64.71%, and 80.49%, respectively. DNMT3a expression was the highest in VLSIL (VIN I) samples, while DNMT1 was only expressed in VHSIL (VIN III) and carcinoma samples. Lichen sclerosis and planus showed a high false positive rate of 45.45% for dysplasia-free and 54.54% for smears with dVIN. Cervical HSIL was associated with a significantly higher number of positive results in the kit than in patients without cervical dysplasia.

CONCLUSIONS

The findings suggest that the methylation markers comprising GynTect® may be suitable for detecting vulvar neoplasia, as they exhibit high sensitivity. Nonetheless, adjustments are needed for comparable specificity. Lichen should be considered in result interpretation, and the kit should be used with caution for patients with lichen. Moreover, we observed methylation changes as an early event with the highest positivity of VLSIL. Surprisingly, changes in methylation pattern are not as local as presumed. Cervical SIL led to changed methylation in the vulva. Patients with positive kit results should be monitored regularly for all genital dysplasia. This sheds new light on the epigenetics in cancer.

Epigenetics as a strategic intervention for early diagnosis and combatting glycolyis-induced chemoresistance in gynecologic cancers

Prospective prediction from the Australian Institute of Health and Welfare (AIHW) showed a likely incidence of 1 in 23 women diagnosed with gynaecological malignancy, where the incidence of relapse with a drug-resistant clone poses a significant challenge in dealing with it even after initial treatment. Glucose metabolism has been exploited as a therapeutic target under anti-metabolomic study, but the non-specificity narrowed its applicability in cancer. Novel updates over epigenetics as a target in gynaecological cancer offer a rational idea of using this in the metabolic rewiring in mutated glycolytic flux-induced drug resistance. This review focuses on the application of epigenetic intervention at a diagnostic and therapeutic level to shift the current treatment paradigm of gynaecological cancers from reactive medicine to predictive, preventive, and personalised medicine. It presents the likely epigenetic targets that can be exploited potentially to prevent the therapeutic failure associated with glucose metabolism-induced chemotherapeutic drug resistance.

Transcriptome Analysis in Vulvar Squamous Cell Cancer

Simple Summary

The number of women, especially younger women, diagnosed with vulvar cancer, has been rising mainly due to the infection with human papilloma virus (HPV) over the last years. In contrast to other tumor entities, limited information on the underlying genetic changes is available, and thus treatment advances, especially the development of personalized treatments, are hampered. We aimed to explore the RNA expression profiles in a group of 24 vulvar cancer samples in order to detect potential prognostic markers and therapeutic targets in order to establish to a more profound understanding of vulvar cancer carcinogenesis.

Abstract

To date, therapeutic strategies in vulvar squamous cell carcinoma (VSCC) are lacking molecular pathological information and targeted therapy hasn’t been approved in the treatment of VSCC, yet. Two etiological pathways are widely accepted: HPV induced vs. HPV independent, associated with chronic skin disease, often harboring TP53 mutations (mut). The aim of this analysis was to analyze the RNA expression patterns for subtype stratification on VSCC samples that can be integrated into the previously performed whole exome sequencing data for the detection of prognostic markers and potential therapeutic targets. We performed multiplex gene expression analysis (NanoString) with 770 genes in 24 prior next generation sequenced samples. An integrative data analysis was performed. Here, 98 genes were differentially expressed in TP53mut vs. HPV+ VSCC, in the TP53mut cohort, where 56 genes were upregulated and 42 were downregulated in comparison to the HPV+ tumors. Aberrant expression was primarily observed in cell cycle regulation, especially in HPV+ disease. Within the TP53mut group, a distinct cluster was identified that was correlated to a significantly worse overall survival (p = 0.017). The RNA expression profiles showed distinct patterns with regard to the known VSCC subtypes and could potentially enable further subclassification in the TP53mut groups

Biomarker Expression in Multifocal Vulvar High-Grade Squamous Intraepithelial Lesions

Simple Summary

In this exploratory study, we aimed to compare biomarker profiles in patients with multiple high-risk human papillomavirus (HPV)-associated vulvar precursor lesions, which is called multifocal high-grade squamous intraepithelial lesion (HSIL). The HPV-positive HSILs were tested for HPV genotype, expression of two immunohistochemical markers p16^INK4a and Ki-67, and DNA methylation of six genes. Generally, the biomarkers showed similar expression between lesions. Occasionally, marked differences were observed, indicating that not all multifocal lesions are the same. Our study contributes to a better understanding of the value of potential diagnostic, prognostic, and predictive biomarkers in patients with vulvar multifocal HSIL. Validation in larger cohorts will be important.

Abstract

In patients with high-grade squamous intraepithelial lesion (HSIL) of the vulva, the presence of multiple lesions, called multifocal HSIL, is common. The aim of this exploratory study was to investigate biomarker expression profiles in multifocal HSIL. In total, 27 lesions from 12 patients with high-risk human papillomavirus (HPV)-positive multifocal HSIL were tested for HPV genotype, expression of p16^INK4a and Ki-67, and DNA methylation of six genes. HPV16 was found most commonly in 21 (77.8%) HSILs. In two (16.4%) patients, HPV genotype differed between the lesions. All lesions demonstrated diffuse p16^INK4a staining, of which three (11.1%) were combined with patchy staining. One patient (8.3%) demonstrated markedly different DNA methylation levels between lesions. Generally, heterogeneity in methylation profiles was observed between different patients, even when other biomarkers showed similar expression. In conclusion, this study is the first to demonstrate heterogeneity of individual lesions in patients with multifocal HSIL. The studied biomarkers have the potential to refine prognostic and predictive diagnostics. Future prospective, longitudinal studies are needed to further explore the potential of a biomarker profile for management of patients with multifocal HSIL.