M.I. Pakharukova

Comparative analysis of morphometric and histological characteristics of HPV-associated and HPV-independent vulvar squamous cell carcinoma

Squamous cell carcinomas of the vulva are divided into human papillomavirus (HPV)-associated and HPV-independent. There is a need to determine the most effective methods for determining the HPV status of a tumor. Differences in the morphological structure of carcinomas have been shown, but the histological type of tumor does not fully reflect the differences in cell size for understanding the mechanisms of carcinogenesis. Objective. To compare the morphometric and histological characteristics of HPV-associated and HPV-independent vulvar carcinomas and to calculate the specificity of histological, immunohistochemical methods and detection of viral DNA in establishing the HPV status of the tumor. Material and methods. The study retrospectively included 74 patients. HPV typing was performed by real-time PCR, expression of p16 and p53 was determined by immunohistochemical method. The total area of tumor cells, the area of the cytoplasm and the nucleus were measured, and the nuclear-cytoplasmic ratio was calculated. Results. HPV-independent carcinomas are predominantly keratinizing (94.3%). HPV-associated carcinomas are of basaloid histotype in 57.1% of cases and keratinizing in 42.9%. (42.9%). HPV-associated tumor cells are smaller (Me 223.89) compared to HPV-independent carcinoma cells (Me 525.95). The nuclear-cytoplasmic ratio was higher in HPV-associated carcinomas (Me 0.46 vs 0.18). The specificity of determining HPV status using histological characteristics of the tumor was 80.65%, immunohistochemical method — 96.36%, detection of viral DNA in the tumor — 75.47%. Conclusion. A smaller cell area and a nuclear-cytoplasmic ratio shift toward the nucleus characterize HPV-associated carcinomas. With HPV-independent carcinogenesis, tumor cells more often retain the ability to differentiate and mature the epithelium. Immunohistochemical determination of p16 and p53 expression is a more accurate method for determining the HPV status of vulvar carcinoma.