Journal of Medical Virology
Distribution of High-Risk Human Papillomavirus Genotypes in HPV-Infected Women in Beijing, China Shuang Lu,1 Xiao Cong,1 Min Li,2 FengXia Chang,3 Liang Ma,1 and Yong Tong Cao1* 1
Molecular Diagnostics Center, Clinical Laboratory, China-Japan Friendship Hospital, Beijing, China Department of Obstetrics and Gynecology, China-Japan Friendship Hospital, Beijing, China 3 Clinical Laboratory, 4th Qing Hai People’s Hospital, QingHai, China 2
To investigate the distribution of high-risk human papillomavirus (HPV) genotypes in infected women from Beijing, China, samples were obtained during routine gynecologic examinations and DNA was extracted from the samples, and PCR was performed to distinguish the 13 high-risk HPV subtypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68). Samples were obtained from 1160 women (20–75 years old), and 470 cases of high-risk HPV infection were diagnosed. HPV 52, HPV 16, HPV 58, HPV 51, and HPV 39 were the most common genotypes accounting for 22.8%, 22.3%, 20.0%, 14.3%, and 13.6% of cases, respectively. The highest infection rates were found in 20–30 year-old patients (35.1%). HPV 16 infection was the highest in the 31–40 yearold group, and HPV 52, HPV 58, and HPV 39 infections were highest in the 20–30 year-old group. Some patients were infected with multiple high-risk HPV subtypes. Of the 470 patients with positive HPV tests, 65.7% of women were infected with a single high-risk HPV subtype, 23.2%, of women were infected with two highrisk HPV subtypes, 7.7% were infected with three subtypes, and 3.4% of women were infected with more than three high-risk HPV subtypes. In this study, HPV 16 and HPV 52 were the most common subtypes found in patients with cervical lesions. J. Med. Virol.
researchers have identified over 100 HPV subtypes and 40 are associated with cervical lesions or cervical cancer. Therefore, HPV are divided into two groups according to their neoplastic potentials. Types that cause low-grade cervical lesions and genital warts are called low risk, and types that cause cervical cancers are called high-risk [Munoz et al., 2003]. The most common high-risk HPV subtypes are 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68. Types 16 and 18 cause approximately 70% of cervical cancers, and 16, 18, 45, 31, 33, 52, 58, and 35 are common HPV types known to cause cervical cancer worldwide [Medeiros et al., 2005]. Limited data are available on the prevalence and types of high-risk HPVs in China and other Asian countries. Several surveys of HPV prevalence have been performed in Hong Kong [Chan et al., 1996; Tay et al., 2008; Chan et al., 2009], Singapore, Japan, and Korea [Bao et al., 2008; Garland et al., 2008; Kim, 2009]. In Mainland China, the prevalence of HPV types differs by geographic area. Thirteen subtypes of high-risk HPV infection were analyzed in this study, and associations with pathological cervical exams in patient samples from the outpatient clinic of the Beijing China–Japan friendship hospital were determined. The goal was to describe the distribution of high-risk HPV subtypes in Beijing China to help inform vaccination and cervical cancer screening strategies.
# 2014 Wiley Periodicals, Inc.
KEY WORDS:
high-risk human papillomavirus (HPV); genotypes; Beijing area
INTRODUCTION Molecular epidemiological studies have shown that high-risk human papillomavirus (HPV) infection is the major etiological factor for cervical cancer [Lorincz et al., 1992; Larson et al., 1997]. To date, C 2014 WILEY PERIODICALS, INC.
Conflict of interest: There are no relevant potential conflicts of interest for each named author and/or a statement of no-conflicts in this article. Grant sponsor: National 863 program of China; Grant number 2011AA02A109 Correspondence to: Yong Tong Cao, MD, Molecular Diagnostics Center, Clinical Laboratory, China-Japan Friendship Hospital, Beijing 100029, China. E-mail: [email protected] Accepted 15 August 2014 DOI 10.1002/jmv.24075 Published online in Wiley Online Library (wileyonlinelibrary.com).
2
Lu et al.
MATERIALS AND METHODS A total of 1160 women who received gynecological examinations as part of their regular routine checkups at the outpatient clinic of the Beijing China Japan Friendship Hospital between September 2012 and April 2013 were included in this retrospective study. Samples were obtained and transferred by a liquid-based media to the molecular laboratory daily. To protect patient confidentiality, participants’ identities and ethnicities were hidden. The research was supervised by the ethical committee of the Beijing China Japan Friendship Hospital. High-Risk HPV Subtype Genotyping HPV detection and typing was done using the highrisk HPV genotyping real time PCR kit (Liferiver, Shanghai, China). The Chinese Food and Drug Administration and the European Certification have approved the method. The commercially available assay detects the 13 high-risk HPV subtypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68) in four separate amplification tubes. Tube 1 is specially designed to detect HPV 16, 56, and 31, and it contains an internal control reaction. Tube 2 can detect HPV 18, 52, 58, and 68. Tube 3 can detect HPV 35, 45, and 33, and tube 4 can detect HPV 39, 51, and 59. Four different fluorescence channels (FAM, VIC, Cy5, and Red610) can separate subtypes in a multiple amplification reaction. Briefly, the reaction is 40 ml and includes 36 ml master mix and 4 ml DNA template. Thermo cycler conditions included an initial denaturation at 94˚C for 2 min followed by 40 cycles of 93˚C for 10 sec and 62˚C for 31 sec. Pathological Diagnosis Subjects who were high-risk HPV positive were referred to the study colposcopist, and punch biopsies were taken from suspicious regions. The period between the HPV infection screening visit and the colposcopy visit was less than three months. Patients with normal or inflamed cervices were classified as negative, and patients with cervical intraepithelial neoplasias were classified as degree I or degree IIþ, which included degree II and III cervical intraepithelial neoplasias and early-stage squamous cervical carcinomas. Statistics Data were analyzed with SPSS (version 10.0). Relative frequencies of HPV genotypes were estimated as percentages. Fisher’s chi-squared were used to compare categorical variables and P-values < 0.05 were considered statistically significant. RESULTS HPV Subtype Distribution in HPV Positive Cases Of the 1160 outpatients, 470 were infected with high-risk HPV subtypes. Thirteen different high-risk J. Med. Virol. DOI 10.1002/jmv
HPV subtypes were identified, including HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68. HPV 52, 16, 58, 51, and 39 were the most common subtypes among the study participants. Among the 470 positive high-risk HPV cases, there were 107 (22.8%) cases of HPV 52, 105 (22.3%) cases of HPV 16, 94 (20.0%) cases of HPV 58, 67 (14.3%) cases of HPV 51, 64 (13.6%) cases of HPV 39, 50 (10.6%) cases of HPV 56, and 47 (10%) cases of HPV 18. Of the 470 highrisk infected women, 309 (65.7%) were infected with one HPV subtype, 109 (23.2%) were infected with two HPV subtypes, 36 (7.7%) were infected with three HPV subtypes, and 16 (3.4%) were infected with more than three subtypes. Age Distribution of High-Risk HPV Subtype Infection Among the 470 infected patients, 165 women (35.1%) were 20–30 years of age, 128 women (27.2%) were 31–40 years of age, 100 women (21.3%) were 51–60 years of age, and 55 women (21.3%) were 51– 60 years of age (Fig. 1). Of the three common HPV subtypes, HPV 52, and HPV 58 were more common in patients 20–30 years of age. However, in women from 30–40 years of age, HPV 16 infection rate was the highest (Table I). Distribution of High-Risk HPV Subtypes in Women With Cervical Lesions Overall, 113 high-risk HPV infected women also presented cervical lesions. These patients underwent cervical biopsies, and the tissues were classified pathologically. In degree I cervical intraepithelial neoplasia cases, HPV 52 was the most common genotype and 13 cases of HPV 52 (29.6%) and nine cases of HPV 16 (20.5%) were documented. Among the 69 degree IIþ cervical intraepithelial neoplasia cases, HPV 16 was the most common genotype (37.7% infection frequency) (Table II). Age Distribution of Patients With High-Risk HPV Infections With Cervical Lesions Pathologically determined cervical intraepithelial neoplasia cases were classified into four groups according to patient age. High-risk HPV infections with degree I cervical lesions were most common in women 20–40 years old (31.8%), and degree IIþ cervical lesions were highest in patients over 41 years old (29.0%) and decreased with increased patient age (Table III). DISCUSSION In this study, 1160 women from the Beijing area participated in high-risk HPV screening, and 470 women tested positive. The results showed that HPV 52 and HPV 16 were the most common subtypes found in 22.8% and 22.3%, respectively, of the study participants. HPV 58, HPV 51, and HPV 39 were also
High-Risk Human Papillomavirus Genotypes in Women
3
Fig. 1. High-Risk HPV subtype infection frequency by patient age group.
TABLE I. HPV 16, HPV 52, and HPV 58 Infection Frequency According to Age HPV subtype Age (years) 60
HPV16
%
HPV52
%
HPV58
%
5 30 36 20 14 1
4.8 28.3 34.0 18.9 13.2 0.9
1 42 29 22 9 4
0.9 39.3 27.1 20.6 8.4 3.7
1 31 26 16 13 7
1.1 33.0 27.7 17.0 13.8 7.5
common and occurred in 20%, 14.3%, and 13.6% of patients, respectively. Pathological exam results showed that HPV 16 was the most frequent genotype associated with cervical lesions. The prevalence of HPV 16 was consistent with previous studies performed in Beijing [Zhao et al., 2006; Li et al., 2010], and the prevalence of HPV 52 was similar to results
reported in Southern China [Huang et al., 1997]. Similarly, another prevalent study of 332 HPV patients from Hong Kong China indicated that the most common high-risk subtypes were HPV 16 (33.3%) and HPV 58 (23.8%) [Chan et al., 1999]. HPV 31 infection rates were significantly higher in women with cervical lesions compared to women with normal or inflamed cervices. Interestingly, the common HPV subtypes 16, 31, 52, and 58 are grouped together on the same branch of the HPV phylogenetic tree, indicating similarities in their pathogenic potentials. Our studies revealed that the overall prevalence of high-risk HPV subtypes differed in women from Beijing compared to other Asian countries. In Korea, HPV18 was the most common subtype followed by HPV 16 and HPV 45. In an epidemiological study of HPV in five Asian countries (South Korea, Singapore, Malaysia, Vietnam, and the Philippines) the prevalence of HPV subtypes was determined in women with invasive cervical cancer and high-grade
TABLE II. Prevalence of HPV Subtypes in Patients With Cervical Intraepithelial Neoplasias Cervical intraepithelial neoplasias (n ¼ 113)
Degree I cervical intraepithelial neoplasias (n ¼ 44)
Degree IIþ cervical intraepithelial neoplasias (n ¼ 69 )
HPV subtype
No.
Total (%)
Single
Multiple
Total (%)
Single
Multiple
Total (%)
16 18 31 33 35 39 45 51 52 56 58 59 68
35 6 16 10 1 14 2 9 23 7 16 7 6
31.0 5.3 14.2 8.9 0.9 12.3 1.8 8.0 20.4 6.2 14.2 6.2 5.3
4 0 5 3 0 2 2 0 9 2 3 0 0
5 3 2 1 1 5 0 2 4 1 3 4 3
20.5 6.8 15.9 9.1 2.3 15.9 4.5 4.6 29.6 6.8 13.6 9.1 6.8
20 2 4 5 0 1 0 4 7 1 6 3 0
6 1 5 1 0 6 0 3 3 3 4 0 3
37.7 4.4 13.0 8.7 0 10.1 0 10.1 14.5 5.8 14.5 4.4 4.4
Includes seven cervical cancer cases.
J. Med. Virol. DOI 10.1002/jmv
4
Lu et al. TABLE III. Prevalence of Cervical Lesions According to Patient Age
Age (years) 20–30 31–40 41–50 51
Degree I cervical intraepithelial neoplasias (n ¼ 44) 31.8% 31.8% 20.5% 13.6%
(14) (14) (9) (6)
Degree II cervical intraepithelial neoplasias (n ¼ 69) 14.5% 27.5% 29.0% 29.0%
(10) (19) (20) (20)
precancerous lesions [Quek et al., 2013]. The results revealed that the most common types observed in invasive cervical cancer samples were HPV 16 (36.8%–61.3%), HPV 18 (12.9%–35.4%), HPV 52 (5.4%–10.3%), and HPV 45 (1.5%–17.2%). In cervical intraepithelial neoplasia patients and cervical cancer patients, HPV 16 (29.7%–46.6%) was the most commonly observed type followed by HPV 52 (17.0%66.7%) and HPV58 (8.6%–16.0%) [Quek et al., 2013]. In the studies of non-Asian regions, HPV 16 and HPV 18 were the most common subtypes. People in America and Europe or South/Central America were more likely to be infected with HPV 18 than those in Asia. In addition, HPV 31 prevalence was high in Europe, HPV 33 was high in South/Central America, and several HPV genotypes (HPV 39, HPV 51, HPV 53, HPV 56, HPV 59, and HPV 66) were more prevalent in North America compared with other regions [Bosch et al., 1995; Clifford et al., 2005]. The association of HPV with patient age also differed from studies in other regions. In this study, the highest infection rates were found in patients 20– 30 years old. At 31–40 years of age, the infection rates of HPV 16 were significantly higher than HPV 52 and HPV 58 infection rates. These differences may result from different clearance rates of HPV 52, HPV 58, and HPV 16. Degree I cervical lesions were most common in women 31–40 years old, and the prevalence of degree IIþ cervical lesions were highest in women 41–50 years old. CONCLUSIONS Regional variations in prevalence and distribution of HPV subtypes have been verified in several epidemiological studies. The study provides important estimates of other prevalent high-risk HPV subtypes (HPV 31, HPV 58, HPV 33, and HPV 52) in preneoplastic lesions. These data will help establish appropriate diagnostic and therapeutic measures in Beijing region and assess the impacts of current vaccines and guide the introduction of new formulations. Although the samples were derived from one hospital, the results may represent the overall population of China. Beijing is the capital city, with 16.9 million populations. Because the hospital accepts patients from many districts and municipalities, expanding the study to include more patients across additional J. Med. Virol. DOI 10.1002/jmv
hospitals will expand on the data derived from the 13 high-risk HPV genotypes studied here. REFERENCES Bao YP, Li N, Smith JS, Qiao YL. 2008. Human papillomavirus type distribution in women from Asia: A meta-analysis. Int J Gynecol Cancer 18:71–79. Bosch FX, Manos MM, Munoz N, Sherman M, Jansen AM, Peto J, Schiffman MH, Moreno V, Kurman R, Shah KV. 1995. Prevalence of human papillomavirus in cervical cancer: A worldwide perspective. International biological study on cervical cancer (IBSCC) Study Group. J Natl Cancer Inst 87:796–802. Chan MK, Lau KM, Tsui Y, Wong FW, Huang DP. 1996. Human papillomavirus infection in Hong Kong Chinese women with normal and abnormal cervix—detection by polymerase chain reaction method on cervical scrapes. Gynecol Oncol 60:217–223. Chan PK, Ho WC, Yu MY, Pong WM, Chan AC, Chan AK, Cheung TH, Wong MC, To KF, Ng HK. 2009. Distribution of human papillomavirus types in cervical cancers in Hong Kong: Current situation and changes over the last decades. Int J Cancer 125:1671–1677. Chan PK, Li WH, Chan MY, Ma WL, Cheung JL, Cheng AF. 1999. High prevalence of human papillomavirus type 58 in Chinese women with cervical cancer and precancerous lesions. J Med Virol 59:232–238. Clifford GM, Rana RK, Franceschi S, Smith JS, Gough G, Pimenta JM. 2005. Human papillomavirus genotype distribution in lowgrade cervical lesions: Comparison by geographic region and with cervical cancer. Cancer Epidemiol Biomarkers Prev 14: 1157–1164. Garland S, Park SN, Ngan HY, Frazer I, Tay EH, Chen CJ, Bhatla N, Pitts M, Shin HR, Konno R, Smith J, Pagliusi S, Park JS. 2008. The need for public education on HPV and cervical cancer prevention in Asia. Opinions of experts at the AOGIN conference. Vaccine 26:5435–5440. Huang S, Afonina I, Miller BA, Beckmann AM. 1997. Human papillomavirus types 52 and 58 are prevalent in cervical cancers from Chinese women. Int J Cancer 70:408–411. Kim YT. 2009. Current status of cervical cancer and HPV infection in Korea. J Gynecol Oncol 20:1–7. Larson AA, Liao SY, Stanbridge EJ, Cavenee WK, Hampton GM. 1997. Genetic alterations accumulate during cervical tumorigenesis and indicate a common origin for multifocal lesions. Cancer Res 57:4171–4176. Li C, Wu M, Wang J, Zhang S, Zhu L, Pan J, Zhang W. 2010. A population-based study on the risks of cervical lesion and human papillomavirus infection among women in Beijing, People’s Republic of China. Cancer Epidemiol Biomarkers Prev 19:2655– 2664. Lorincz AT, Reid R, Jenson AB, Greenberg MD, Lancaster W, Kurman RJ. 1992. Human papillomavirus infection of the cervix: Relative risk associations of 15 common anogenital types. Obstet Gynecol 79:328–337. Medeiros R, Prazeres H, Pinto D, Macedo-Pinto I, Lacerda M, Lopes C, Cruz E. 2005. Characterization of HPV genotype profile in squamous cervical lesions in Portugal, a southern European population at high-risk of cervical cancer. Eur J Cancer Prev 14:467–471. Munoz N, Bosch FX, de Sanjose S, Herrero R, Castellsague X, Shah KV, Snijders PJ, Meijer CJ. 2003. Epidemiologic classification of human papillomavirus types associated with cervical cancer. N Engl J Med 348:518–527. Quek SC, Lim BK, Domingo E, Soon R, Park JS, Vu TN, Tay EH, Le QT, Kim YT, Vu BQ, Cao NT, Limson G, Pham VT, Molijn A, Ramakrishnan G, Chen J. 2013. Human papillomavirus type distribution in invasive cervical cancer and high-grade cervical intraepithelial neoplasia across five countries in Asia. Int J Gynecol Cancer 23:148–156. Tay SK, Ngan HY, Chu TY, Cheung AN, Tay EH. 2008. Epidemiology of human papillomavirus infection and cervical cancer and future perspectives in Hong Kong, Singapore, and Taiwan. Vaccine 26:M60–M70. Zhao Fh, Forman MR, Belinson J, Shen Yh, Graubard BI, Patel AC, Rong Sd, Pretorius RG, Qiao Yl. 2006. Risk factors for HPV infection and cervical cancer among unscreened women in a high-risk rural area of China. Int J Cancer 118:442–448.
Distribution of High-Risk Human Papillomavirus Genotypes in HPV-Infected Women in Beijing, China Shuang Lu,1 Xiao Cong,1 Min Li,2 FengXia Chang,3 Liang Ma,1 and Yong Tong Cao1* 1
Molecular Diagnostics Center, Clinical Laboratory, China-Japan Friendship Hospital, Beijing, China Department of Obstetrics and Gynecology, China-Japan Friendship Hospital, Beijing, China 3 Clinical Laboratory, 4th Qing Hai People’s Hospital, QingHai, China 2
To investigate the distribution of high-risk human papillomavirus (HPV) genotypes in infected women from Beijing, China, samples were obtained during routine gynecologic examinations and DNA was extracted from the samples, and PCR was performed to distinguish the 13 high-risk HPV subtypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68). Samples were obtained from 1160 women (20–75 years old), and 470 cases of high-risk HPV infection were diagnosed. HPV 52, HPV 16, HPV 58, HPV 51, and HPV 39 were the most common genotypes accounting for 22.8%, 22.3%, 20.0%, 14.3%, and 13.6% of cases, respectively. The highest infection rates were found in 20–30 year-old patients (35.1%). HPV 16 infection was the highest in the 31–40 yearold group, and HPV 52, HPV 58, and HPV 39 infections were highest in the 20–30 year-old group. Some patients were infected with multiple high-risk HPV subtypes. Of the 470 patients with positive HPV tests, 65.7% of women were infected with a single high-risk HPV subtype, 23.2%, of women were infected with two highrisk HPV subtypes, 7.7% were infected with three subtypes, and 3.4% of women were infected with more than three high-risk HPV subtypes. In this study, HPV 16 and HPV 52 were the most common subtypes found in patients with cervical lesions. J. Med. Virol.
researchers have identified over 100 HPV subtypes and 40 are associated with cervical lesions or cervical cancer. Therefore, HPV are divided into two groups according to their neoplastic potentials. Types that cause low-grade cervical lesions and genital warts are called low risk, and types that cause cervical cancers are called high-risk [Munoz et al., 2003]. The most common high-risk HPV subtypes are 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68. Types 16 and 18 cause approximately 70% of cervical cancers, and 16, 18, 45, 31, 33, 52, 58, and 35 are common HPV types known to cause cervical cancer worldwide [Medeiros et al., 2005]. Limited data are available on the prevalence and types of high-risk HPVs in China and other Asian countries. Several surveys of HPV prevalence have been performed in Hong Kong [Chan et al., 1996; Tay et al., 2008; Chan et al., 2009], Singapore, Japan, and Korea [Bao et al., 2008; Garland et al., 2008; Kim, 2009]. In Mainland China, the prevalence of HPV types differs by geographic area. Thirteen subtypes of high-risk HPV infection were analyzed in this study, and associations with pathological cervical exams in patient samples from the outpatient clinic of the Beijing China–Japan friendship hospital were determined. The goal was to describe the distribution of high-risk HPV subtypes in Beijing China to help inform vaccination and cervical cancer screening strategies.
# 2014 Wiley Periodicals, Inc.
KEY WORDS:
high-risk human papillomavirus (HPV); genotypes; Beijing area
INTRODUCTION Molecular epidemiological studies have shown that high-risk human papillomavirus (HPV) infection is the major etiological factor for cervical cancer [Lorincz et al., 1992; Larson et al., 1997]. To date, C 2014 WILEY PERIODICALS, INC.
Conflict of interest: There are no relevant potential conflicts of interest for each named author and/or a statement of no-conflicts in this article. Grant sponsor: National 863 program of China; Grant number 2011AA02A109 Correspondence to: Yong Tong Cao, MD, Molecular Diagnostics Center, Clinical Laboratory, China-Japan Friendship Hospital, Beijing 100029, China. E-mail: [email protected] Accepted 15 August 2014 DOI 10.1002/jmv.24075 Published online in Wiley Online Library (wileyonlinelibrary.com).
2
Lu et al.
MATERIALS AND METHODS A total of 1160 women who received gynecological examinations as part of their regular routine checkups at the outpatient clinic of the Beijing China Japan Friendship Hospital between September 2012 and April 2013 were included in this retrospective study. Samples were obtained and transferred by a liquid-based media to the molecular laboratory daily. To protect patient confidentiality, participants’ identities and ethnicities were hidden. The research was supervised by the ethical committee of the Beijing China Japan Friendship Hospital. High-Risk HPV Subtype Genotyping HPV detection and typing was done using the highrisk HPV genotyping real time PCR kit (Liferiver, Shanghai, China). The Chinese Food and Drug Administration and the European Certification have approved the method. The commercially available assay detects the 13 high-risk HPV subtypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68) in four separate amplification tubes. Tube 1 is specially designed to detect HPV 16, 56, and 31, and it contains an internal control reaction. Tube 2 can detect HPV 18, 52, 58, and 68. Tube 3 can detect HPV 35, 45, and 33, and tube 4 can detect HPV 39, 51, and 59. Four different fluorescence channels (FAM, VIC, Cy5, and Red610) can separate subtypes in a multiple amplification reaction. Briefly, the reaction is 40 ml and includes 36 ml master mix and 4 ml DNA template. Thermo cycler conditions included an initial denaturation at 94˚C for 2 min followed by 40 cycles of 93˚C for 10 sec and 62˚C for 31 sec. Pathological Diagnosis Subjects who were high-risk HPV positive were referred to the study colposcopist, and punch biopsies were taken from suspicious regions. The period between the HPV infection screening visit and the colposcopy visit was less than three months. Patients with normal or inflamed cervices were classified as negative, and patients with cervical intraepithelial neoplasias were classified as degree I or degree IIþ, which included degree II and III cervical intraepithelial neoplasias and early-stage squamous cervical carcinomas. Statistics Data were analyzed with SPSS (version 10.0). Relative frequencies of HPV genotypes were estimated as percentages. Fisher’s chi-squared were used to compare categorical variables and P-values < 0.05 were considered statistically significant. RESULTS HPV Subtype Distribution in HPV Positive Cases Of the 1160 outpatients, 470 were infected with high-risk HPV subtypes. Thirteen different high-risk J. Med. Virol. DOI 10.1002/jmv
HPV subtypes were identified, including HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68. HPV 52, 16, 58, 51, and 39 were the most common subtypes among the study participants. Among the 470 positive high-risk HPV cases, there were 107 (22.8%) cases of HPV 52, 105 (22.3%) cases of HPV 16, 94 (20.0%) cases of HPV 58, 67 (14.3%) cases of HPV 51, 64 (13.6%) cases of HPV 39, 50 (10.6%) cases of HPV 56, and 47 (10%) cases of HPV 18. Of the 470 highrisk infected women, 309 (65.7%) were infected with one HPV subtype, 109 (23.2%) were infected with two HPV subtypes, 36 (7.7%) were infected with three HPV subtypes, and 16 (3.4%) were infected with more than three subtypes. Age Distribution of High-Risk HPV Subtype Infection Among the 470 infected patients, 165 women (35.1%) were 20–30 years of age, 128 women (27.2%) were 31–40 years of age, 100 women (21.3%) were 51–60 years of age, and 55 women (21.3%) were 51– 60 years of age (Fig. 1). Of the three common HPV subtypes, HPV 52, and HPV 58 were more common in patients 20–30 years of age. However, in women from 30–40 years of age, HPV 16 infection rate was the highest (Table I). Distribution of High-Risk HPV Subtypes in Women With Cervical Lesions Overall, 113 high-risk HPV infected women also presented cervical lesions. These patients underwent cervical biopsies, and the tissues were classified pathologically. In degree I cervical intraepithelial neoplasia cases, HPV 52 was the most common genotype and 13 cases of HPV 52 (29.6%) and nine cases of HPV 16 (20.5%) were documented. Among the 69 degree IIþ cervical intraepithelial neoplasia cases, HPV 16 was the most common genotype (37.7% infection frequency) (Table II). Age Distribution of Patients With High-Risk HPV Infections With Cervical Lesions Pathologically determined cervical intraepithelial neoplasia cases were classified into four groups according to patient age. High-risk HPV infections with degree I cervical lesions were most common in women 20–40 years old (31.8%), and degree IIþ cervical lesions were highest in patients over 41 years old (29.0%) and decreased with increased patient age (Table III). DISCUSSION In this study, 1160 women from the Beijing area participated in high-risk HPV screening, and 470 women tested positive. The results showed that HPV 52 and HPV 16 were the most common subtypes found in 22.8% and 22.3%, respectively, of the study participants. HPV 58, HPV 51, and HPV 39 were also
High-Risk Human Papillomavirus Genotypes in Women
3
Fig. 1. High-Risk HPV subtype infection frequency by patient age group.
TABLE I. HPV 16, HPV 52, and HPV 58 Infection Frequency According to Age HPV subtype Age (years) 60
HPV16
%
HPV52
%
HPV58
%
5 30 36 20 14 1
4.8 28.3 34.0 18.9 13.2 0.9
1 42 29 22 9 4
0.9 39.3 27.1 20.6 8.4 3.7
1 31 26 16 13 7
1.1 33.0 27.7 17.0 13.8 7.5
common and occurred in 20%, 14.3%, and 13.6% of patients, respectively. Pathological exam results showed that HPV 16 was the most frequent genotype associated with cervical lesions. The prevalence of HPV 16 was consistent with previous studies performed in Beijing [Zhao et al., 2006; Li et al., 2010], and the prevalence of HPV 52 was similar to results
reported in Southern China [Huang et al., 1997]. Similarly, another prevalent study of 332 HPV patients from Hong Kong China indicated that the most common high-risk subtypes were HPV 16 (33.3%) and HPV 58 (23.8%) [Chan et al., 1999]. HPV 31 infection rates were significantly higher in women with cervical lesions compared to women with normal or inflamed cervices. Interestingly, the common HPV subtypes 16, 31, 52, and 58 are grouped together on the same branch of the HPV phylogenetic tree, indicating similarities in their pathogenic potentials. Our studies revealed that the overall prevalence of high-risk HPV subtypes differed in women from Beijing compared to other Asian countries. In Korea, HPV18 was the most common subtype followed by HPV 16 and HPV 45. In an epidemiological study of HPV in five Asian countries (South Korea, Singapore, Malaysia, Vietnam, and the Philippines) the prevalence of HPV subtypes was determined in women with invasive cervical cancer and high-grade
TABLE II. Prevalence of HPV Subtypes in Patients With Cervical Intraepithelial Neoplasias Cervical intraepithelial neoplasias (n ¼ 113)
Degree I cervical intraepithelial neoplasias (n ¼ 44)
Degree IIþ cervical intraepithelial neoplasias (n ¼ 69 )
HPV subtype
No.
Total (%)
Single
Multiple
Total (%)
Single
Multiple
Total (%)
16 18 31 33 35 39 45 51 52 56 58 59 68
35 6 16 10 1 14 2 9 23 7 16 7 6
31.0 5.3 14.2 8.9 0.9 12.3 1.8 8.0 20.4 6.2 14.2 6.2 5.3
4 0 5 3 0 2 2 0 9 2 3 0 0
5 3 2 1 1 5 0 2 4 1 3 4 3
20.5 6.8 15.9 9.1 2.3 15.9 4.5 4.6 29.6 6.8 13.6 9.1 6.8
20 2 4 5 0 1 0 4 7 1 6 3 0
6 1 5 1 0 6 0 3 3 3 4 0 3
37.7 4.4 13.0 8.7 0 10.1 0 10.1 14.5 5.8 14.5 4.4 4.4
Includes seven cervical cancer cases.
J. Med. Virol. DOI 10.1002/jmv
4
Lu et al. TABLE III. Prevalence of Cervical Lesions According to Patient Age
Age (years) 20–30 31–40 41–50 51
Degree I cervical intraepithelial neoplasias (n ¼ 44) 31.8% 31.8% 20.5% 13.6%
(14) (14) (9) (6)
Degree II cervical intraepithelial neoplasias (n ¼ 69) 14.5% 27.5% 29.0% 29.0%
(10) (19) (20) (20)
precancerous lesions [Quek et al., 2013]. The results revealed that the most common types observed in invasive cervical cancer samples were HPV 16 (36.8%–61.3%), HPV 18 (12.9%–35.4%), HPV 52 (5.4%–10.3%), and HPV 45 (1.5%–17.2%). In cervical intraepithelial neoplasia patients and cervical cancer patients, HPV 16 (29.7%–46.6%) was the most commonly observed type followed by HPV 52 (17.0%66.7%) and HPV58 (8.6%–16.0%) [Quek et al., 2013]. In the studies of non-Asian regions, HPV 16 and HPV 18 were the most common subtypes. People in America and Europe or South/Central America were more likely to be infected with HPV 18 than those in Asia. In addition, HPV 31 prevalence was high in Europe, HPV 33 was high in South/Central America, and several HPV genotypes (HPV 39, HPV 51, HPV 53, HPV 56, HPV 59, and HPV 66) were more prevalent in North America compared with other regions [Bosch et al., 1995; Clifford et al., 2005]. The association of HPV with patient age also differed from studies in other regions. In this study, the highest infection rates were found in patients 20– 30 years old. At 31–40 years of age, the infection rates of HPV 16 were significantly higher than HPV 52 and HPV 58 infection rates. These differences may result from different clearance rates of HPV 52, HPV 58, and HPV 16. Degree I cervical lesions were most common in women 31–40 years old, and the prevalence of degree IIþ cervical lesions were highest in women 41–50 years old. CONCLUSIONS Regional variations in prevalence and distribution of HPV subtypes have been verified in several epidemiological studies. The study provides important estimates of other prevalent high-risk HPV subtypes (HPV 31, HPV 58, HPV 33, and HPV 52) in preneoplastic lesions. These data will help establish appropriate diagnostic and therapeutic measures in Beijing region and assess the impacts of current vaccines and guide the introduction of new formulations. Although the samples were derived from one hospital, the results may represent the overall population of China. Beijing is the capital city, with 16.9 million populations. Because the hospital accepts patients from many districts and municipalities, expanding the study to include more patients across additional J. Med. Virol. DOI 10.1002/jmv
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