Human papillomavirus prevalence in invasive cervical carcinomas in Bulgaria

Although Bulgaria has one of the highest rates of cervical cancer incidence and mortality in the EU, data on HPV type distribution are limited.

To determine the prevalence of HPV types 16 and 18 in archival specimens from cervical cancer cases from Bulgaria.

A total of 145 formalin-fixed, paraffin-embedded tissue samples from women with histologically proven invasive squamous cell carcinoma of the uterine cervix were available for this study. Detection of HPV types 16 and 18 was based on two parallel PCRs from each sample using type-specific primers for these genotypes. The quality of the extracted DNA was evaluated by PCR using PC03/PC04 β-globin-specific primers. Sections from each block were H&E stained and assessed by the study pathologist to confirm the histological diagnosis.

Of the 127 β-globin-positive squamous cell carcinoma cases, 98 (77.2%) were positive for HPV16 and/or HPV18 DNA. HPV16 was the more prevalent type and was found as a single infection in 86 (67.7%) cases. HPV type 18 as a single infection was detected in eight (6.3%) cases. Four specimens (3.2%) were double infected with HPV types 16 and 18.

HPV types 16 and 18 are important risk factors for cervical cancer in Bulgaria. These data are helpful for estimating the potential impact of HPV vaccines in Bulgaria and indicate that ∼77% of cervical cancer cases in the country are potentially preventable by vaccination with currently available prophylactic HPV16/18 vaccines.