Prevalence and viral load of oncogenic human papillomavirus types associated with cervical carcinoma in a population of North Italy

Abstract

A cross-sectional study was carried out in a population of North Italy to determine the prevalence of eight oncogenic human papillomavirus (HPV) types most commonly found in cervical carcinoma and to study the relationship between HPV DNA loads and severity of disease. A total of 597 cervical samples obtained from patients with pathological findings (n = 472) and from women with normal cytology (n = 125) were analyzed by means of normalized Real-time PCR assays to quantify HPV-16, -18, -31, -45, and -33 group (including -33, -52, -58, -67); the normalization of oncogenic HPV viral load was carried out by quantitation of a single copy gene. The two most common oncogenic HPV types found were 16 and 31 (24.3% and 22.9% of pathological samples, respectively); multiple infections were demonstrated in 22% of pathological samples. Overall, the HPV total viral load was found to increase with increasing severity of associated lesions, although a stronger association was observed only for HPV-31 and HPV-16 (gamma = 0.49 and 0.41, respectively) as compared to HPV-18 and -33 group (gamma = 0.19 and 0.02, respectively). However, we found that high levels of HPV-31 or 33 group DNA could be prognostic of minor oncogenic risk for high-grade squamous intraepithelial lesions (H-SIL) (age adjusted odds ratio [AORs] = 1.57 and 1.26, respectively) than HPV-16 and HPV-18 (AORs = 30 and 8, respectively). The AORs also increased with HPV total viral load and reached a maximum of AORs = 15.7. Thus, HPV load is a type-dependent risk marker for the development of H-SIL.