Absence of p53 protein overexpression in precancerous lesions of the vulva.

BACKGROUND Recently the authors reported the prognostic value of p53 protein overexpression in invasive squamous cell carcinoma of the vulva. The aim of this study was to evaluate the status of p53 overexpression and human papillomavirus (HPV) infection in patients with precancerous lesions of the vulva. METHODS Biopsy specimens of 28 women (mean age, 44.2 years; range, 19-71 years) with warty and/or basaloid type vulvar intraepithelial neoplasia (VIN) of Grade 1 to 3 were examined retrospectively for p53 protein overexpression by immunohistochemistry. The presence of the HPV genome was assessed using a nested polymerase chain reaction (PCR) method with consensus primers directed against the L1 coding region. RESULTS Neither the preoperative punch biopsy specimen nor the subsequent surgical specimen contained immunohistochemically detectable levels of p53 in this study of a group of younger women with preinvasive vulvar lesions. These results are in contrast to those obtained previously in older women with keratinizing squamous cell carcinoma demonstrating p53 protein overexpression in approximately 50% of patients. HPV DNA was detected in the vast majority of VIN cases (92.8%) using a highly sensitive nested PCR method. The current data indicate that p53 protein is not overexpressed in basaloid/warty VIN when evaluated by immunohistochemistry. In addition, this study confirms previous reports demonstrating the presence of HPV DNA in the majority of these lesions. CONCLUSIONS These data suggest that p53 protein overexpression is not an early event in the pathogenesis of basaloid/warty type vulvar dysplasia and that HPV infection may contribute to the development of VIN. Cancer 1998;82:323-7. © 1998 American Cancer Society.