Distribution of high and low risk HPV types by cytological status: a population based study from Italy.

BACKGROUND: HPV type distribution by cytological status represents useful information to predict the impact of mass vaccination on screening programs. METHODS: women aged from 25 to 64 who attended cervical cancer screening in five different Italian regions were tested for HPV infection with Hybrid Capture II (HCII) low and high risk probes. Women repeating Pap-test upon unsatisfactory or positive results, or as a post-treatment and post-colposcopy follow-up analysis, were excluded from our study. High risk (HR) HPV positive samples were typed using GP5+/GP6+ primed PCR, followed by Reverse Line Blot for 18 high/intermediate risk HPV types, while low risk (LR) HPV positive samples were tested with type specific primers for HPV6 and HPV11. RESULTS: 3410 women had a valid HCII and Pap-test. The prevalence of HR and LR infections was 7.0% and 3.6%, 29.1% and 13.7%, 68.1% and 31.9%, 60.0% and 0.0%, 65.0% and 12.0%, for negative, ASC-US, L-SIL, ASC-H and H-SIL cytology, respectively. The fraction of ASC-US+ cytology due to HPV 16 and 18 ranged from 11.2 (HPV 16/18 alone) to 15.4% (including HPV 16/18 in co-infection with other virus strains), and that due to HPV 6 and 11 ranged from 0.2% (HPV 6/11 alone) to 0.7% (including HPV 6/11 in co-infection with other LR virus strains). CONCLUSIONS: mass vaccination with bivalent or quadrivalent HPV vaccine would modestly impact on prevalence of abnormal Pap-test in screening.

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 <35 years to 73% 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.