High HPV-51 Prevalence in Invasive Cervical Cancers: Results of a Pre-Immunization Survey in North Sardinia, Italy

BACKGROUND: Human Papilloma virus (HPV) is recognized as the etiological agent of benign and malignant ano-genital lesions. The most prevalent genotypes associated with cervical carcinoma are HPV-16 and -18 worldwide. However, recent studies have emphasized the role of other genotypes, such as HPV-51, in the pathogenesis of cervical dysplasia. The aim of the study was to estimate the burden of HPV-51 infection in invasive cervical malignant lesions in Northern Sardinia, Italy. METHODS/PRINCIPAL FINDINGS: An observational, retrospective, prevalence, mono-center study was carried out to evaluate the presence of HPV genotypes in tissues biopsies of cervical lesions (CIN-1, CIN-2, CIN-3 and invasive carcinoma) gathered from 1996 to 2009. Biological samples were collected from women admitted consecutively to a tertiary university hospital situated in Sassari, Italy. Molecular methods were used to identify 28 oncogenic HPV types. A total of 155 formalin-fixed and paraffin-embedded cervical tissue samples were analyzed. Approximately half of the cervical lesions were classified as invasive carcinoma. HPV-DNA was detected in 71% of the samples, with a higher frequency (100%) in those categorized as invasive neoplasia. Mono- or co-infections were demonstrated in 45.8% and 25.8% of the cervical samples, respectively. Overall, the most prevalent HPV types were -16 (49%) and -51 (19.4%), with an increased frequency of detection associated with the severity of the cervical lesions. CONCLUSIONS/SIGNIFICANCE: This survey highlights for the first time the relevant role of HPV-51 infection in the pathogenesis of invasive cervical cancer prior to the introduction of a vaccination program. Although a selection bias could have influenced the results, other recent studies have described the impact of HPV-51. This remarkable epidemiological element should be carefully evaluated, particularly in the view of opting for preventive vaccines, whose cross-protection patterns determine their efficacy in protecting against infection from HPV types that are not included in the vaccine itself.