Human papillomavirus in squamous cell carcinoma of the vulva by polymerase chain reaction

To investigate the prevalence of human papillomavirus (HPV) DNA in squamous cell carcinoma of the vulva by polymerase chain reaction (PCR).

Archival diagnostic phase biopsies from 74 patients with squamous cell carcinoma of the vulva were investigated for HPV DNA by PCR. We used both consensus primers located in the open reading frame L1 and type-specific primers for HPV 6 (open reading frame E5), HPV 11 (open reading frame L1), HPV 16, HPV 18, and HPV 33 (open reading frame E6).

HPV DNA was detected in 27 (36%) of the 74 patients, of whom 19 had HPV 16, nine had HPV 18, one had HPV 33, and one had unclassified HPV DNA. No case of HPV type 6 or 11 was detected. Two squamous cell carcinomas were positive for both HPV 16 and 18, and one was positive for both HPV types 16 and 33. Three squamous cell carcinomas positive for E6 gene using type-specific primers were negative using L1 consensus primers.

Our PCR methods using both consensus open reading frame L1-derived primers and type-specific open reading frame E6-derived primers of HPV types 16, 18, and 33 seemed to be an appropriate combination for the detection of HPV DNA in archival tissues of vulvar carcinoma. Both HPV types 16 and 18 were associated with squamous cell carcinoma of the vulva, although the prevalence of HPV 16 was considerably lower than in cervical carcinoma. It appears that vulvar and cervical carcinomas are not identical etiologically and that factors other than HPV are important in vulvar carcinogenesis.