Distribution of Human Papillomavirus 16 E6/E7 Variants in Cervical Cancer and Intraepithelial Neoplasia in Chinese Women

Introduction: Human papillomavirus (HPV) type 16 is the major etiological agents of cervical cancer. Recently, the studies have demonstrated that HPV intratypic variations could affect oncogenic potential to cervical cancer development. The objectives of this study were to identify HPV-16 E6 and E7 variants prevalent in Chinese women and to assess the risk of them for invasive cervical carcinoma and cervical intraepithelial neoplasia (CIN). Methods: DNA samples were genotyped by flow-through hybridization (HybriMax) and amplified by using primers specific for E6 and E7. Products were directly sequenced and analyzed using BLAST on PubMed. Results: A total of 170 cervical samples (33 cases of normal control, 11 of CIN 1, 72 of CIN 2-3, and 54 of invasive cervical carcinoma) were HPV-16-positive and were analyzed for E6 and E7 sequence variation. The results showed that HPV-16 Asian lineage was the most frequently detected (77%) and that the Asian variant presented a significantly higher disease risk for cervical cancer and CIN. In addition, 3 novel variants at E6 (Q20P, H118Q, and Q123K) and 2 at E7 (D75N and T86P) were found. The substitution G368T at E6 leading to a premature stop codon occurred in an isolate of normal control sample. Conclusions: This study reported the distribution of HPV-16 E6 and E7 gene variations in women from southeastern China, which are different from that showed in previous studies and may be important when developing an effective vaccine for this area.