BackgroundType-specific high-risk HPV (hrHPV) infection is related to cervical carcinogenesis. The prevalence of hrHPV infection varies geographically, which might reflect the epidemiological characteristics of cervical cancer among different populations. To establish a foundation for HPV-based screening and vaccination programs in China, we investigated the most recent HPV prevalence and genotypic distributions in different female age groups and geographical regions in China.MethodsIn 2012, a total of 120,772 liquid-based cytological samples from women enrolled for population- or employee-based cervical screening in 37 Chinese cities were obtained by the Laboratory of Molecular Infectious Diseases of Guangzhou KingMed. A total of 111,131 samples were tested by Hybrid Capture II and the other 9,641 were genotyped using the Tellgenplex™ HPV DNA Assay.ResultsThe total positive rate for hrHPV was 21.07 %, which ranged from 18.42 % (Nanchang) to 31.94 % (Haikou) and varied by region. The regions of Nanchang, Changsha, Hangzhou, Chengdu, Fuzhou, Guangdong, and Guiyang could be considered the low prevalence regions. Age-specific prevalence showed a “two-peak” pattern, with the youngest age group (15–19 years) presenting the highest hrHPV infection rate (30.55 %), followed by a second peak for the 50–60-year-old group. Overall, the most prevalent genotypes were HPV16 (4.82 %) and HPV52 (4.52 %), followed by HPV58 (2.74 %). Two genotypes HPV6 (4.01 %) and HPV11 (2.29 %) were predominant in the low-risk HPV (lrHPV) type, while the mixed genotypes HPV16 + 52 and HPV52 + 58 were most common in women with multiple infections.ConclusionsThis study shows that HPV infection in China has increased to the level of an “HPV-heavy-burden” zone in certain regions, with prevalence varying significantly among different ages and regions. Data from this study represent the most current survey of the nationwide prevalence of HPV infection in China, and can serve as valuable reference to guide nationwide cervical cancer screening and HPV vaccination programs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-015-0998-5) contains supplementary material, which is available to authorized users.

Introduction: The prevalence of cervical Human Papillomavirus (HPV) infection varies greatly worldwide and data regarding HPV prevalence and genotypes in China are limited.Methods: HPV testing results were retrospectively examined at KingMed Diagnostics, the largest independent pathology laboratory in China, from January 2011 to June 2014. All testing was performed using the 26 HPV Genotyping Panel of TellgenplexTM xMAP™ HPV DNA Test assay (TELLGEN, Shanghai, China). Overall prevalence, age-specific prevalence and genotype distributions were analyzed.Results: A total of 51,345 samples were tested and the overall HPV prevalence was 26%, with 21.12% positive for high risk (HR) HPV and 8.37% positive for low risk HPV. 80% of HPV positive cases were positive for a single HPV type. The three most common HR HPV types detected were HPV-52, -16, and -58, in descending order. HPV-18 was only the 6th most common type. When women were divided into three age groups: <30, 30-49, ≥50 years, HR HPV had the highest prevalence rate in women <30 years, and the lowest rate in women 30-49 years of age. The distribution of HR HPV genotypes also varied among these three age groups.Conclusions: To the best of our knowledge, this is largest routine clinical practice report of HPV prevalence and genotypes in a population of women having limited cervical cancer screening. HPV-52 was the most prevalent HR HPV type in this population of women followed by HPV-16 and HPV-58. The overall and age-specific prevalence and genotype distribution of HR HPV are different in this Chinese population compared to that reported from Western countries.

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Resistance associated substitutions (RASs) can reduce the efficacy of direct-acting antiviral agents (DAAs) targeting hepatitis C virus (HCV) and lead to treatment failure. Clinical data of HCV NS5A RASs prevalence are limited in China and need to be investigated. A total of 878 unique patient samples with different genotypes (GT) (1b: n = 489, 2a: n = 203, 3a: n = 60, 3b: n = 78, 6a: n = 48) were collected from around mainland China by KingMed Laboratory and analyzed for NS5A RASs distribution by Sanger sequencing. Phylogeographic analyses based on NS5A domain 1 sequences indicated circulation of both locally and nationally epidemic strains. Relatively high frequency of Y93H (14.1%) was only detected in GT1b but not in other subtypes. High frequency of L31M was found in both GT2a (95.6%) and GT3b (98.7%) sequences. Due to the overlapping incidence of A30K, 96% of GT3b isolates had NS5A RASs combination A30K + L31M, which confers high levels of resistance to most NS5A inhibitors. No RASs were detected in GT6a strains. Meanwhile, baseline NS5A RASs fingerprints were also evaluated in 185 DAA treatment-naive GT1b patients with next generation sequencing method. Patients presenting with Y93H had statistically higher entropy of HCV NS5A sequences. Taken together, subtype-specific distribution patterns of NS5A RASs were observed. GT1b patients with higher HCV complexity tend to have a greater chance of Y93H presence, while GT3b patients are naturally resistant to current NS5A inhibitors and their treatment may pose a challenge to real-world DAA application.

Context.— Reports for atypical squamous cells of undetermined significance (ASC-US) and histologic findings are rare in China. Objective.— To analyze the correlation findings of ASC-US cytology with high-risk human papillomavirus (hrHPV) test and histopathologic follow-ups. Design.— ASC-US cases with hrHPV test and histologic follow-ups between 2011 and 2015 were analyzed at a College of American Pathologists–certified laboratory. Results.— A total of 2 206 588 Papanicolaou (Pap) tests were performed, including 1 513 265 liquid-based cytology preparations (68.58%), and 693 323 conventional Pap tests (31.42%). The overall ASC-US reporting rate was 3.77% (83 199 of 2 206 588), with the highest in women aged 40 to 49 years. Of 18 574 women with ASC-US Pap and HPV testing, the hrHPV positivity rate was 34.98% (6498 of 18 574) with the highest in women younger than 30 years. A total of 6012 women with ASC-US Pap test findings had histologic follow-ups within 6 months; the overall cervical intraepithelial neoplasia 2 and above (CIN2+) detection rate was 7.87% (473 of 6012). One thousand nine hundred nine women with ASC-US Pap and HPV testing had histologic results. CIN2+ lesion was found in 13.98% (124 of 887) of women with ASC-US Pap/HPV-positive test results, significantly higher than 2.84% (29 of 1022) for women with ASC-US Pap/HPV-negative test results. Cervical squamous cell carcinoma was found in 3.95% (35 of 887) of women with ASC-US/HPV-positive test results. Conclusions.— This is one of the largest studies to investigate HPV and histologic follow-up findings in women with ASC-US in China. The ASC-US reporting rate, HPV positivity rate, and CIN2+ detection rate were all within the currently recognized benchmark ranges. These findings may contribute to establishing a baseline for better understanding of the status of cervical screening in China.

Our findings demonstrate that negative hrHPV testing on cervicovaginal cytology specimens in women later diagnosed with cervical carcinoma can be explained by the occurrence of truly HPV-negative carcinomas in more than half of patients. These results should be considered in the development of future cervical cancer screening guidelines.

Objectives Extended high-risk human papillomavirus (hrHPV) genotype testing has recently been introduced in routine cervical cancer screening. Changes in national and regional hrHPV genotype prevalence offer an objective baseline indicator of the future impact of mass HPV vaccination and HPV-based cervical screening. Methods This retrospective study reports nationwide hrHPV genotyping results from July 2018 to June 2019 in 29 KingMed Diagnostics laboratories throughout China. Results In total, 2,458,227 hrHPV genotyping results were documented from KingMed’s nationwide laboratory database during the study period. The overall prevalence of hrHPV-positive results was 19.1%, with twin peaks for highest hrHPV infection rates in women younger than 30 years of age (22.0%) and 50 years of age and older (21.8%). The most frequently detected hrHPV genotypes were HPV-52 (4.7%), HPV-16 (3.4%), HPV-53 (2.5%), HPV-58 (2.4%), HPV-51 (2.0%), and HPV-68 (1.6%). Overall, hrHPV-positive results varied regionally from 15.3% to 24.4%. Conclusions Nationwide hrHPV genotyping results from KingMed laboratories offer a baseline for measuring the future impact of large-scale HPV vaccination. High hrHPV infection rates in older (≥50 years) Chinese women likely reflect the limited extent of cervical screening in China. High rates of hrHPV infection and variable regional hrHPV genotype distribution may represent limiting factors for cost-effective implementation of hrHPV-based cervical screening in China.

Skyrmion bags are found in liquid crystals and predicted to exist in ferromagnetic films. They are expected to become the information carriers of the new generation racetrack memory due to their high-degree of freedom of topological charge number. Here, we numerically and theoretically investigate the dynamics of skyrmion bags driven by the spin–orbit torque in an infinite ferromagnetic film and a nanostrip with a finite length. It is found that the constant velocity of the skyrmion bag in the ferromagnetic film depends on its topological charge number, while in the case of motion in nanostrips with the skyrmion bag moving along the boundary, the velocity in the first approximation is independent of the topological charge number. The simulation results are in good agreement with the calculation results. Finally, we show that the skyrmion bag can pass through defects and impurities in the nanostrip due to topological protection. Our results reveal the dynamics of skyrmion bags driven by the spin–orbit torque and may also be beneficial for the development of racetrack memory based on skyrmion bags.