Prevalence of human papillomavirus types in high-grade cervical intraepithelial neoplasia and cancer in Italy

Background: The aim of this multicentric study was to identify human papillomavirus (HPV) type distribution in invasive cervical cancer and high-grade cervical intraepithelial neoplasia 2/3 (CIN2/3) in Italy. Methods: Cases were sampled through the electronic databases at the pathology units of eight centers in six regions from central and southern Italy. HPV types were detected from paraffin-embedded tissue samples and cervical specimens through amplification of HPV DNA with GP5+/GP6+ primers, followed by genotyping with reverse line blot (RLB). Untyped HPV-positive samples were sequenced. HPV-negative samples underwent nested PCR, followed by either RLB or sequencing. Finally, the remaining HPV-negative samples were amplified with primers targeting the virus E6 to E7 regions. Results: From 1,162 cases initially selected, 722 samples were further analyzed: 144 CIN2, 385 CIN3, 157 invasive squamous carcinomas, and 36 adenocarcinomas. Samples (6.9%) were HPV negative. The proportion of HPV16/18 was 60.8%, 76.6%, and 78.8% in CIN2, CIN3, and invasive cancers, respectively (P trend = 0.004). There was a significant decreasing trend of HPV16/18 with age in invasive cancers, going from 92% in women 55 years (P = 0.036). The proportion of coinfections was 16.8%, 15.5%, and 10.0% in CIN2, CIN3, and invasive cancers, respectively (P trend = 0.07). Conclusions: The proportion of invasive cancers caused by HPV16/18 decreases with age at diagnosis. Impact: The absolute risk of an invasive cancer due to non-HPV16/18 in women under 35 is extremely low. This finding might prompt us to rise the age at which public HPV screening for vaccinated women should start.