International Journal of Urology (2010) 17, 563–569

Original Article: Clinical Investigation

doi: 10.1111/j.1442-2042.2010.02521.x, 10.1111/j.1442-2042.2010.02531.x

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563..569

Prevalence of human papillomavirus infection in the urinary tract of men with urethritis Kazuyoshi Shigehara,1 Toshiyuki Sasagawa,2 Syohei Kawaguchi,1 Yoshitomo Kobori,3 Takao Nakashima,3 Masayoshi Shimamura,3 Tadashi Taya,4 Keiichi Furubayashi5 and Mikio Namiki1 1

Department of Integrative Cancer Therapy and Urology, Kanazawa University Graduate School of Medical Science, Kanazawa, Ishikawa, 2Department of Reproductive and Perinatal Medicine, Kanazawa Medical University, Kahoku, Ishikawa, 3Department of Urology, Ishikawa Prefectural Central Hospital, Kanazawa, 4Taya Urological Clinic, Komatsu, Ishikawa, and 5Furubayashi Clinic, Osaka, Japan

Objectives: To investigate the prevalence of human papillomavirus (HPV) in the genital and urinary tract of men with urethritis. Methods: Cell samples were collected from the penis, urethra and urine of 142 men with urethritis. A HPV test was performed on the samples using the modified GP5+/6+ polymerase chain reaction method , and the HPV genotype was determined using a HPV GenoArray test. Results: Out of 142 urethritis patients, HPV was detected in 48% (68 cases), and high-risk HPV was found in 32% (46 cases) of patients, on their penis or in the urinary tract (urethra or urine). HPV was detected in 31% in the penis, 20% in the urethra and 24% in the urine, while high-risk HPV was identified in 23% in the penis, 12% in the urethra and 11% in the urine. Among the HPV-positive men, 66% had HPV infection in the urinary tract where the most common HPV types were HPV6, HPV16, HPV18 and HPV58. Single HPV-type infection was more frequently found in the urinary tract (89%) than in the penis (65%) (P < 0.05). Conclusions: Similar to the penis, the urinary tract represents a common HPV infection site in men with urethritis. Key words: HPV genotyping, human papillomavirus, urethritis, urinary tract.

Introduction Cervical cancer is the second common cancer in women worldwide.1 Since the discovery of human papillomavirus (HPV) 16 and 18 DNA in cervical cancer tissue by zur Hausen’s group,2 more than 100 types of HPV have been isolated and at least 15 types of high-risk HPV have been identified.3 Cervical HPV infection appears to occur in more than 50% of young women within a few years of their sexual debut4 and 70–80% of women are likely to have the infection for all of their life.5 Thus, cervical HPV infection is thought to be one of the most common sexually transmitted infections in women. The incidence of cervical cancer in young women is increasing in many countries including Japan. In contrast, the role of HPV infection in men’s cancer is controversial and only 40% of penile cancer, which is most likely associated with HPV infection in men, is caused by HPV infection in Correspondence: Toshiyuki Sasagawa MD PhD, Department of Reproductive and Perinatal Medicine, Kanazawa Medical University, Daigaku, Uchinada-machi, Kahoku-gun, Ishikawa 9200293, Japan. Email: [email protected] Received 11 November 2009; accepted 21 February 2010. Online publication 23 March 2010 © 2010 The Japanese Urological Association

men.6 Moreover, penile cancer is very rare and its incidence is estimated to range from 0.2 to 2.2 per 100 000 per year, and generally develops in men over 60 years of age.6 Therefore, sexually transmitted HPV infection in men has not attracted much attention from researchers. Currently, the prophylactic anti-HPV16 and 18 vaccine has been available to prevent cervical cancer in young women around the world , and could lead to reducing the incidence of cervical cancer by approximately 70% in the future.7 On the other hand , vaccination of men is being discussed as a way of eliminating HPV infection in the generation who have been vaccinated , and some researchers have regarded the HPV prevalence in men only as a reservoir for HPV transmission, which could be a cause of cervical cancer. Some recent studies have shown that HPV prevalence in men is equivalent to that of women.8,9 The most common infection sites for HPV in men are reported to be in the penile glans and shaft and the scrotum, but not common in the urinary tract.10,11 However, we have recently found that HPV prevalence in urine samples is much higher in men who have urethritis than in age-adjusted healthy controls.12 In the present study, we investigated the prevalence of HPV and common HPV genotypes in samples of urine, the urethra and penis of Japanese men with urethritis. 563

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Methods

(a) (a) (b)

Subjects The subjects were composed of 156 male patients with urethritis who visited the outpatient clinics of Kanazawa University Hospital (Kanazawa, Japan), Ishikawa Prefectural Central Hospital (Kanazawa, Japan), Taya Urological Clinic (Komatsu, Japan) and a sexually transmitted disease (STD) clinic in Osaka (Japan) between 2007 and 2008. Out of 156 patients with urethritis, 142 agreed to participate in the present study and written informed consent approved by the ethics committee of Kanazawa University Graduate School of Medicine was obtained from each of them. The patients with apparent lesions such as condyloma acuminate were eliminated in this study. The mean age ⫾ standard deviation of the participants was 35.2 ⫾ 9.9 years (range, 19–62 years). Diagnosis of urethritis was based on pyuria that showed more than five white blood cells in high-power fields and/or the presence of urinary symptoms such as pain on urination, urethral discomfort and pus discharge. All patients with urethritis were tested for Neisseria gonorrhoeae and Chlamydia trachomatis in first-catch urine or urethral swab, based on the Aptima Combo 2 Assay (Gen-Probe, San Diego, CA, USA) or Amplicor STD-1 PCR (Roche Diagnostics, Basel, Switzerland).

Sampling Samples from the penis, distal urethra and urine were collected from all 148 participants. To obtain a sample from the penis, cells were collected by rubbing the entire surface of the glans, coronary sulcus and prepuce with a saline-wetted cotton tip. The urethral samples were collected with a salinewetted cotton tip by insertion approximately 3 cm into the urethra, and rubbing up and down. For the urine samples, 50 mL of urine was centrifuged at 1500 r.p.m. (approximately 504 g) for 10 min and the sediment was stored at –30°C until DNA analysis. The cells collected from the penis and urethra were placed into a separate tube containing 2.5 mL of preservative solution for liquid-based cytology (Liqui-PREP; LGM International Inc., Fort Lauderdale, FL, USA) and were stored at 4°C until use.

HPV-DNA test and HPV genotyping Aliquots of 1 mL of preservative solution containing cell samples were centrifuged at 5000 r.p.m. (approximately 504 g) for 5 min, and the supernatant was discarded. The cell pellet was washed twice with 300 mL of 10 mmol/L Tris-Cl (pH 8.0). DNA was extracted from the cells using a DNA extraction kit (SMI test; G & G Science Co., Fukushima, Japan) according to the manufacturer’s instructions. 564

(b)

(c)

(d)

(e)

Fig. 1 Human papillomavirus (HPV) GenoArray Kit (a) hybridization positive control and (b) inner control gene. (A) HPV negative. (B) HPV6 positive. (C) HPV16 positive. (D) HPV18 positive. (E) HPV45 and HPV68 positive.

DNA quality was confirmed by amplifying the b-globin gene as an internal control by polymerase chain reaction (PCR), as described previously.13 In the present study, only b-globin gene-positive samples were tested for HPV. The presence of HPV-DNA was examined using modified GP5+/ GP6+ PCR, as reported previously.13 HPV-DNA was amplified using about 10–50 ng of sample DNA in 10 mL of PCR solution containing 8 mmol/L MgCl2, 200 mmol/L deoxynucleotide triphosphate, 10¥ PCR buffer (Toyobo, Tokyo, Japan), 20 pmol of each primer and 0.25 units of KOD Dash DNA polymerase (Toyobo, Tokyo, Japan). PCR was performed according to the following program: one cycle of 5 min at 95°C, 30 s at 55°C and 30 s at 74°C, followed by 40 cycles of 30 s at 95°C, 30 s at 48°C and 30 s at 74°C. HPV was defined as positive when a band of approximately 140 bp was observed after electrophoresis of 8 mL of PCR product on 2.5% agarose gels and staining with ethidium bromide. HPV genotyping was performed in HPV-positive samples using a HPV GenoArray Test Kit (HybriBio Ltd , Chaozhou, China). This assay is able to determine 21 HPV types including 14 high-risk HPV types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68), 5 low-risk HPV types (6, 11, 42, 43 and 44) and two unknown risk types (53 and CP8304), by the flow-through hybridization technique using HPV DNA amplified by PCR. Aliquots of 25 mL of heat-denatured PCR solution were used for flowthrough hybridization analysis according to the manufacturer’s protocol. The HPV type was determined by visualization of blue spots at the position of each HPV type probe on the membrane (Fig. 1). Some samples that were positive on the HPV screening test that did not show any positive signals in the genotyping test were classified as infection with unknown HPV types. © 2010 The Japanese Urological Association

Human papillomavirus in men

Table 1 Prevalence of human papillomavirus (HPV) infection in 142 men with urethritis b-globin positive rate

Any HPV positive High-risk HPV positive Low-risk HPV positive Multiple HPV infection

Glans (n = 127) 89%

Urethra (n = 132) 93%

Urine (n = 92) 65%

Urinary tract (n = 142)

Overall (n = 142)

n (%)

n (%)

n (%)

n (%)

n (%)

40 (31%) 29 (23%) 15 (12%) 14 (11%)

26 (20%) 16 (12%) 11 (8.3%) 4 (3.0%)

22 (24%) 10 (11%) 10 (11%) 2 (2.2%)

45 (32%) 26 (18%) 23 (16%) 5 (3.5%)

68 (48%) 46 (32%) 26 (18%) 15 (11%)

Overall indicates the number and rate of HPV detection at any site. Urinary tract includes HPV detection from urethral sample or urine sample. n, number of adequate samples.

Statistical analysis All statistical analyses were performed using the c2 test or Fisher’s exact probability test to compare categorical variables. P < 0.05 was considered as significant.

no condyloma acuminata, suggesting that many asymptomatic infections occur even in HPV6 and HPV11. Most of the high-risk HPV types and one low-risk type, HPV43, did not induce apparent lesions on the penis. The HPV type could not be determined (unknown type) in three patients.

Results Among 142 urethritis patients, 29 had gonococcal infection, 34 had chlamydial infection, one had both infections and 78 had non-gonococcal and non-chlamydial urethritis. There were no significant differences in HPV prevalence according to the causative microorganisms for urethritis. No apparent lesions such as condyloma acuminata were observed in the 142 subjects. The b-globin gene was positive in 89% of samples from the penis, 93% from the urethra and 65% of the urine samples (Table 1). Any type of HPV was detected in 48% (68 cases) of urethritis patients, and high-risk HPV was detected in 32% (46 cases). The prevalence of any type of HPV was 31% from the penis, 20% from the urethra and 24% in the urine samples, indicating that the penis was the most common site. When we counted the urine and urethral samples together, as being from the same resource (the urinary tract), the prevalence was almost the same between the penis and the urinary tract. HPV was positive in the urinary tract in 66% (45 cases) of 68 HPV-positive patients. Therefore, the urinary tract was a common HPV infection site in men with urethritis. The high-risk HPV type was detected in 23% of the penis and 18% of the urinary tract (12% of the urethra and 11% of the urine). Although multiple HPV-type infection was frequently identified on the penis (14/40; 35%), single HPV-type infection was more frequent (40/45; 89%) in the urinary tract (P < 0.05). In all of the sites, HPV16 was the most common type, followed by HPV types 6, 18, 58, 43, 52, 68 and 39 (Table 2). HPV16, 18 and 58 were common high-risk types, while HPV6 and 43 were common low-risk types. Low-risk HPV types were detected in 26 urethritis patients who had © 2010 The Japanese Urological Association

Discussion A HPV vaccine has been available to prevent cervical cancer in young women around the world. On the other hand , there have been some arguments about whether a vaccination for men would be necessary to eliminate HPV infection in the population who have been vaccinated. However, nobody knows the details of HPV transmission from men to women, and what parts of the male genital tract are the source of HPV transmission. Furthermore, there is another important question as to whether HPV induces malignant tumor of the male genital tract or not. Therefore, the epidemiology of HPV infection in men is an important issue for men’s health. We demonstrated that overall HPV prevalence was 48% in men with urethritis in the present study. Some previous reports indicate that the prevalence of HPV infection on the male external genitalia in 17- to 70-year-old men visiting STD clinics ranges from 28% to 45%.14–16 It has recently been reported that HPV prevalence among 1160 healthy men (18 to 70 years old) from Brazil, Mexico and the USA was 65.2% in samples combined from the penile glans, coronal sulcus, penile shaft and scrotum.17 Although it is difficult to compare that data directly, because the target age, population and the site of samples differs, the prevalence observed in the present study is a little less than that reported in Mexico and the USA. On the other hand , a previous study in another Japanese group has shown that HPV prevalence on the penile glans is 18.5% in 130 patients (17 to 49 years) with urethritis,18 showing a lower HPV-positive rate than that in the present study. The hybrid capture-2 method , which is detectable for both high-risk and low-risk HPV, was used in the previously mentioned Japanese study. Although 565

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Table 2 Human papillomavirus (HPV)-type distribution of 68 HPV-positive urethritis patients

High-risk type 16 18 31 33 39 45 52 58 59 68 Intermediate-risk type 53 CP8034 Low-risk type 6 11 43 Unknown type

Glans (n = 40)

Urethra (n = 26)

Urine (n = 22)

Urinary tract (n = 45)

Overall (n = 68)

n

n

n

n

n

16 8 1 ND 2 1 1 6 2 2

7 5 ND ND ND ND 4 1 1 1

3 4 ND 1 1 ND ND 3 ND 1

10 9 ND 1 1 ND 4 4 1 2

21 16 1 1 3 1 5 10 2 4

1 1

ND ND

ND 1

ND 1

1 2

10 1 4 1

9 ND 3 ND

8 ND 3 2

14 ND 6 2

18 1 9 2

Urinary tract includes HPV detection from urethral sample or urine sample. ND, not detected.

hybrid capture assays are widely used to detect clinically relevant HPV infection, limitations of this method include an inability to identify specific HPV types, and lower analytical but not necessarily clinical sensitivity compared with the PCR method.19 A higher HPV prevalence in the present study might be due to higher sensitivity and broader ranges of HPV type detection using the present PCR method.13The HybriBio HPV GeniArray Kit used in the present study is a commercial kit that has been recently introduced into the market, and this assay is able to determine 21 HPV types by the flow-through hybridization technique. This array has shown good agreement (93.8%) in detection of HPV types with the results by the Amplicor HPV test.20 According to a systematic review on the prevalence of HPV infection among men, external genitalia including the penile shaft, glans, coronal sulcus and prepuce are the sites with a high prevalence of HPV infection in asymptomatic men.10 Giuliano et al. has reported that asymptomatic HPV infection is frequently observed in the penile shaft (49.9%), followed by the glans (35.8%), scrotum (34.2%), perianal area (20.0%), anal area (17.6%) and the urethra (10.1%), indicating that HPV prevalence is lowest in the urethra.10 Other reports have also indicated HPV prevalence rates of urethral samples ranging from 8.7% to 30%,21–23 and HPV prevalence in urine samples ranging from 0.9% to 6.9%, even in analysis of adequate samples in which the internal 566

control gene is detected ,11,16,21,24 suggesting that urinary tract HPV infection is not so common in sexually active men. However, we have shown that HPV-DNA is detected in 1.9% (3/160) of healthy men, whereas it is in 24% (7/29) of the urine from urethritis men.12 In the present study, we have clearly shown that the urinary tract is a common HPV infection site, and the prevalence of HPV infection is equivalent to that in the penis of men with urethritis. We could identify high HPV detection in the urinary tract of men with urethritis. Some studies suggested that urine specimens could be of value in the assessment of HPV infection in cases with intrameatal warts or urethral infection.25,26Because inflammation induced by some microorganisms can contribute to cell exfoliation, urethritis leads to easier detection of asymptomatic HPV infection in men with urethritis than healthy men.26 Alternatively, urethritis itself might increase the risk of HPV infection in the urinary tract, because micro-injury is necessary for HPV to access the basal cells of the epithelium. However, the detection rate of b-globin gene in urine samples by the PCR-based method has been poorer than that of penile and urethral rubbed samples. Improvement in DNA detection by the PCR-based method should be required if we test HPV-DNA using urine samples. Some studies indicated a high prevalence of low-risk HPV infection such as HPV6 and HPV11 (range, 8–20%) in © 2010 The Japanese Urological Association

Human papillomavirus in men

men without condyloma acuminata in their genitalia.16,17,27,28 This was supported by the findings in the present study. Thus, asymptomatic HPV infection not only with high-risk HPV but also with low-risk HPV types appears to be more common in male genitalia than we have expected. Examination by peniscopy or urethroscopy would be quite important to confirm the presence of invisible lesions of asymptomatic condyloma acuminate or penile intraepithelial neoplasia, which appears after acetic acid treatment, as routinely performed in women who undertake colposcopic examination for cervical cancer screening.29 It was reported that HPV59 is most frequently detected , followed by HPV84, HPV16 and HPV6 in the external genitalia of healthy men in Mexico.29 HPV84, HPV62, HPV6 and HPV18 were detected frequently in the penile glans, coronal sulcus, penile shaft and scrotum of 1160 healthy men who had no definite STD.17 In the present study, the common HPV types on the penis were HPV16, HPV6, HPV18, HPV52 and HPV58. HPV-type distributions are likely to differ between different regions. It is noteworthy that HPV58 and 52 were common, which have been described as common HPV types in Japanese women.30,31 HPV-type distributions are likely to differ between different regions. Multiple HPV-type infection is commonly seen in the cervix of women.31 Similarly, we have demonstrated multiple-type infection was observed in 46% of penile samples positive for HPV. It is observed on the external genitalia in 51% of healthy Mexican men.27 Multiple HPVtype infections might also be commonly observed in male external genitalia. In contrast, 89% of urinary tract HPV infection was single-type infection. Generally, multiple-type HPV infection is common in low-grade cervical intraepithelial lesions, while single-type infection is known as a sign of presence of higher grade cervical lesions or cancer.31 Some studies have noted that single-type HPV infection was detected in urothelial inverted papilloma and bladder cancer.32–35 Therefore, we are concerned that a single-type HPV infection occurring in the urinary tract might be associated with the presence of some urological tumors or its precursor lesions, if the infection is persistent for a long time. However, further study is needed to warrant this hypothesis, and we are going to start further HPV studies to explore the role of HPV infection in the development of urogenital tumor.

References 1 Walboomers JM, Jacobs MV, Manos MM et al. Human Papillomavirus is a necessary cause of invasive cervical cancer worldwide. J. Pathol. 1999; 189: 12–19. 2 zur Hausen H. Papillomaviruses in anogenital cancer as a model to understand the role of viruses in human cancers. Cancer Res. 1989; 49: 4677–81.

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3 Lorincz AT, Reid R, Jenson AB, Greenberg MD, Lancaster W, Kurman RJ. Human papillomavirus infection of the cervix: relative risk associations of 15 common anogenital types. Obstet. Gynecol. 1992; 79: 328–37. 4 Winer RL, Feng Q, Hughes JP, O’Reilly S, Kiviat NB, Koutsky LA. Risk of female human papillomavirus acquisition associated with first male sex partner. J. Infect. Dis. 2008; 197: 279–82. 5 Smith JS, Melendy A, Rana RK, Pimenta JM. Age-specific prevalence of infection with human papillomavirus in females: a global review. J. Adolesc. Health 2008; 43 (Suppl): S5–25. 6 Rubin MA, Kleter B, Zhou M et al. Detection and typing of human papillomavirus DNA in penile carcinoma: evidence for multiple independent pathways of penile carcinogenesis. Am. J. Pathol. 2001; 159: 1211–18. 7 Konno R, Shin HR, Kim YT et al. Human papillomavirus infection and cervical cancer prevention in Japan and Korea. Vaccine 2008; 26 (Suppl 12): M30–42. 8 Castellsagué X, Bosch FX, Muñoz N et al. Male circumcision, penile human papillomavirus infection, and cervical cancer in female partners. N. Engl. J. Med. 2002; 346: 1105–12. 9 Giraldo PC, Eleutério J Jr, Cavalcante DI, Gonçalves AK, Romão JA, Eleutério RM. The role of high-risk HPV-DNA testing in the male sexual partners of women with HPV-induced lesions. Eur. J. Obstet. Gynecol. Reprod. Biol. 2008; 137: 88–91. 10 Dunne EF, Nielson CM, Stone KM, Markowitz LE, Giuliano AR. Prevalence of HPV infection among men: a systematic review of the literature. J. Infect. Dis. 2006; 194: 1044–57. 11 Giuliano AR, Nielson CM, Flores R et al. The optimal anatomic sites for sampling heterosexual men for human papillomavirus (HPV) detection: the HPV detection in men study. J. Infect. Dis. 2007; 196: 1146–52. 12 Kobori Y, Sasagawa T, Taya T, Hasegawa T, Fukushima K, Namiki M. Detection and genotyping of human papillomavirus DNA in the urine of healthy men and in the urine of male patients with urethritis. Jpn J. Sex. Transm. Dis. 2008; 19: 118–21 (in Japanese). 13 Yamada R, Sasagawa T, Kirumbi LW et al. Human papillomavirus infection and cervical abnormalities in Nairobi, Kenya, an area with a high prevalence of human immunodeficiency virus infection. J. Med. Virol. 2008; 80: 847–55. 14 Baldwin SB, Wallace DR, Papenfuss MR et al. Human papillomavirus infection in men attending a sexually transmitted disease clinic. J. Infect. Dis. 2003; 187: 1064–70. 15 Svare EI, Kjaer SK, Worm AM, Osterlind A, Meijer CJ, van den Brule AJ. Risk factors for genital HPV DNA in men resemble those found in women: a study of male attendees at a Danish STD clinic. Sex. Transm. Infect. 2002; 78: 215–18. 16 Lazcano-Ponce E, Herrero R, Muñoz N et al. High prevalence of human papillomavirus infection in Mexican

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males: comparative study of penile-urethral swabs and urine samples. Sex. Transm. Dis. 2001; 28: 277–80. Giuliano AR, Lazcano-Ponce E, Villa LL et al. The human papillomavirus infection in men study: human papillomavirus prevalence and type distribution among men residing in Brazil, Mexico, and the United States. Cancer Epidemiol. Biomarkers Prev. 2008; 17: 2036–43. Takahashi S, Shimizu T, Takeyama K et al. Detection of human papillomavirus DNA on the external genitalia of healthy men and male patients with urethritis. Sex. Transm. Dis. 2003; 30: 629–33. Partridge JM, Koutsky LA. Genital human papillomavirus infection in men. Lancet Infect. Dis. 2006; 6: 21–31. Grisaru D, Avidor B, Niv J et al. Pilot study of prevalence of high-risk human papillomavirus genotypes in Israeli Jewish women referred for colposcopic examination. J. Clin. Microbiol. 2008; 46: 1602–5. Forslund O, Hansson BG, Rymark P, Bjerre B. Human papillomavirus DNA in urine samples compared with that in simultaneously collected urethra and cervix samples. J. Clin. Microbiol. 1993; 31: 1975–9. Aguilar LV, Lazcano-Ponce E, Vaccarella S et al. Human papillomavirus in men: comparison of different genital sites. Sex. Transm. Infect. 2006; 82: 31–3. Nicolau SM, Camargo CG, Stávale JN et al. Human papillomavirus DNA detection in male sexual partners of women with genital human papillomavirus infection. Urology 2005; 65: 251–5. Weaver BA, Feng Q, Holmes KK et al. Evaluation of genital sites and sampling techniques for detection of human papillomavirus DNA in men. J. Infect. Dis. 2004; 189: 677–85. Melchers WJ, Schift R, Stolz E, Lindeman J, Quint WG. Human papillomavirus detection in urine samples from male patients by the polymerase chain reaction. J. Clin. Microbiol. 1989; 27: 1711–14. Hillman RJ, Botcherby M, Ryait BK, Hanna N, Taylor-Robinson D. Detection of human papillomavirus DNA in the urogenital tracts of men with anogenital warts. Sex.Transm. Dis. 1993; 20: 21–7.

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27 Lajous M, Mueller N, Cruz-Valdéz A et al. Determinants of prevalence, acquisition, and persistence of human papillomavirus in healthy Mexican military men. Cancer Epidemiol. Biomarkers Prev. 2005; 14: 1710–16. 28 Bleeker MC, Hogewoning CJ, Berkhof J et al. Concordance of specific human papillomavirus types in sex partners is more prevalent than would be expected by chance and is associated with increased viral loads. Clin. Infect. Dis. 2005; 41: 612–20. 29 Bleeker MC, Snijders PF, Voorhorst FJ, Meijer CJ. Flat penile lesions: the infectious “invisible” link in the transmission of human papillomavirus. Int. J. Cancer 2006; 119: 2505–12. 30 Inoue M, Sakaguchi J, Sasagawa T, Tango M. The evaluation of human papillomavirus DNA testing in primary screening for cervical lesions in a large Japanese population. Int. J. Gynecol. Cancer 2006; 16: 1007–13. 31 Sasagawa T, Basha W, Yamazaki H, Inoue M. High-risk and multiple human papillomavirus infections associated with cervical abnormalities in Japanese women. Cancer Epidemiol. Biomarkers Prev. 2001; 10: 45–52. 32 Moonen PM, Bakkers JM, Kiemeney LA, Schalken JA, Melchers WJ, Witjes JA. Human papilloma virus DNA and p53 mutation analysis on bladder washes in relation to clinical outcome of bladder cancer. Eur. Urol. 2007; 52: 464–8. 33 Barghi MR, Hajimohammadmehdiarbab A, Moghaddam SM, Kazemi B. Correlation between human papillomavirus infection and bladder transitional cell carcinoma. BMC Infect. Dis. 2005; 5: 102. 34 Chan KW, Wong KY, Srivastava G. Prevalence of six types of human papillomavirus in inverted papilloma and papillary transitional cell carcinoma of the bladder: an evaluation by polymerase chain reaction. J. Clin. Pathol. 1997; 50: 1018–21. 35 Tekin MI, Tuncer S, Aki FT, Bilen CY, Aygün C, Ozen H. Human papillomavirus associated with bladder carcinoma? Analysis by polymerase chain reaction. Int. J. Urol. 1999; 6: 184–6.

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Editorial Comment to Prevalence of human papillomavirus infection in the urinary tract of men with urethritis In this article, the authors clearly showed that the detection rate of human papillomavirus (HPV) in the urethra was 22% and that in urine it was 24% in patients with male urethritis. The authors concluded that the urinary tract is a common HPV infection site in such men and that HPV infection in the urinary tract is equivalent to that in the penis. In the era of HPV vaccination, there have been some arguments as to whether vaccination for men is necessary or not. Therefore, the details of male HPV infection or colonization must be 568

clarified. On that point, the authors presented invaluable discussion and suggestions. From another angle, some urologists believe that “asymptomatic” HPV infection must be a common disease in humans because most cases of HPV infection are transient, even though many men and women have HPV infection or colonization in the external genitalia due to sexual intercourse. In addition, some urologists indicate that they do not necessarily care whether such infection develops or not. © 2010 The Japanese Urological Association