Human Papillomavirus Infection in Croatian Men: Prevalence and HPV Type Distribution

Abstract

Human papillomavirus (HPV) infection has been identified as a major risk factor for cervical intraepithelial neoplasia (CIN) and invasive cervical cancer (zur Hausen, 2002; Bosch et al., 2002; Munoz et al., 2003). HPV infection is one of the most common sexually transmitted infections, generally asymptomatic, with the worldwide prevalence in women with normal cytology of 11.4% (11.3-11.5%; 95%CI) (WHO/ICO Information Centre on HPV and Cervical Cancer. Summary report 2010). Epidemiological studies in the USA have reported that 75% of the 15-50 year-old population is infected with genital HPV during their lifetime. Among those, 60% are with transient infection, 10% with persistent infection (confirmed by detection of HPV-DNA in genital samples), 4% with mild cytological signs, and 1% with clinical lesions (WHO/ICO Information Centre on HPV and Cervical Cancer. Papillomavirus and Related Cancers in United States of America. Summary Report 2010). To date, more than 100 genotypes of HPV have been identified, with more than 40 anogenital types, at least 15 of which are oncogenic (Munoz et al. 2003; Clifford et al., 2005). Anogenital HPV types have been further classified into low-risk types (lrHPV, e.g., 6 and 11), which are associated with anogenital warts and mild dysplasia, and high-risk types (hrHPV, e.g., 16, 18, 31, and 33), which are associated with high-grade dysplasia and anogenital cancers, such as cervical and anal carcinoma. (Bosch et al., 2002; Smith et al., 2007). In Croatia, HPV testing is widely used as a secondary test to triage borderline cytology and as a follow-up after treatment of severe cervical lesions, in addition to conventional cytological screening (Grce et al., 2007). Grahovac et al. (2007) investigated the HPV prevalence and type distribution among 361 women regularly attending gynecological examinations, and showed 67.9% overall prevalence of hrHPV in women with abnormal PAP smears compared to 35.6% in women with normal cytology. Study done by Hadžisejdic et al., (2006) on prevalence of HPV genotypes in cervical cancer also revealed high prevalence of HPV-DNA in cervical lesions; 93% in CIN III, 92.6% in squamous cell carcinoma (SCC) and 92.5% in adenocarcinoma (ADC).