Associations of high-risk HPV types and viral load with cervical cancer in China

Abstract

Background Cervical cancer is the second most common cancer in women worldwide. Infection with some genotypes of human papillomavirus is the most important risk factor associated with cervical cancer. Objective The aim of this study was to determine the prevalence and genotypes of HPV in China, and to evaluate the correlation between viral load of high risk HPV and cervical cancer and its precursors. Study design A cross-sectional study was carried out, wherein cervical samples were collected from 541 patients with cervical cancer, 262 with CIN, 139 with cervicitis and 68 age-matched healthy controls. Hybrid Capture 2 was employed to detect HPV DNA. Specimens from HPV DNA positive cervical cancer were tested for HPV types by using type specific PCR and general primer PCR with sequence-based typing (GP PCR-SBT). Results Overall high risk HPV prevalence was 68.8% in CIN1, 80.3% in CIN2, 90.2% in CIN3, 90.9% in cervical cancer in situ, 89.9% in invasive cervical cancer and 25% in healthy controls from China. The most common HPV DNA type found in patients with cervical cancer was HPV16 (79.6%), followed by HPV58 (5.92%), HPV33 (3.29%), HPV18 (1.97%), HPV6 (1.97%), HPV31 (1.31%), HPV39 (1.31%), HPV68 (1.31%) and other HPV types (3.3%). It was found that there was a significantly increased risk of increasing CIN stage with high viral load. Frequency of low viral load found in the controls was 13.2% and 22.9% of CIN1, obtaining an OR of 4.2 (1.5–12.0). Associations (OR) among low viral load and CIN2/3, CIS, and CC were 6.7 (2.9–15.6), 9.4 (2.7–32.3) and 8.3 (3.7–18.4), respectively. While high viral loads were found in 5.9% of controls, 27.1% of CIN1, 42.1% of CIN2/3 and 48.5% of CIS, demonstrating increasing odds ratios with severity of disease (OR for CIS = 68.0, 95% CI = 17.8–259.7). Conclusions HPV16 was the most common genotype in central China. The developing cervical cancer precursors were associated with elevated high-risk HPV viral load.