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. 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.