Purpose: The aim of this study was to analyze the diagnostic performance of a newly established immunocytochemical dual-staining protocol for the simultaneous expression of SEC62 and Ki67 in vulvar liquid-based cytology specimens for the identification of vulvar intraepithelial neoplasia (VIN) and vulvar cancer. In addition, we investigated the p16/Ki67 dual stain, which has already been established in cervical cytology.
Materials and methods: For this pilot study, residual material from liquid-based cytology was collected retrospectively from 45 women. The presence of one or more double-immunoreactive cells was considered as a positive test result for Sec62/Ki67 and p16/Ki67 dual staining. The test results were correlated with the course of histology.
Results: All cases of VIN and vulvar cancer were Sec62/Ki67 and p16/Ki67 dual-stain positive, and normal and low-grade squamous intraepithelial lesions were all negative. The sensitivity of cytology for VIN + cases was 100% (22/22), whereas punch biopsy classified one case of vulvar carcinoma as inflammation. All cases with high-intensity (grades 3 and 4) Sec62 staining in Sec62/Ki67-positive cases were carcinomas.
Conclusions: The results of this study demonstrate that Sec62/Ki67 and p16 Ki67 dual-staining cytology could be a promising adjunctive diagnostic tool for VIN and squamous cell carcinoma, in addition to standard histology.
Keywords: Immunocytochemistry; Ki67; Sec62; Vulvar cancer; Vulvar cytology; Vulvar intraepithelial neoplasia.