Jinichi Sakamoto

Effectiveness of prophylactic HPV vaccines against cervical abnormalities and HPV infection in Japan: The J‐HERS 2021 multicenter study

Abstract This study investigated the efficacy of the prophylactic human papillomavirus (HPV) vaccine, which was initiated between 2009 and 2013 in Japan. The study involved 1529 eligible women aged 16–39 years who visited 11 outpatient clinics in Japan for various reasons. These patients underwent HPV genotype analysis and a Pap test of cervical cell samples. A total of 299 women (19.6%) had received the prophylactic HPV vaccine (bivalent:quadrivalent vaccine ratio = 2:1). Of the 5062 participants in the Japanese Human Papillomavirus Disease Education and Research Survey (J‐HERS 2011), which was conducted in the pre‐vaccination era, 3236 eligible participants were included as controls. In this study (J‐HERS 2021), the highest rate of HPV vaccination (53%) was observed in patients aged 22–27 years. Vaccinated individuals exhibited a 49% rate of protection against low‐grade intraepithelial lesions (LSILs) and atypical squamous cells, not excluding high‐grade squamous intraepithelial lesions (ASCH) or worse (LSIL/ASCH+), and a 100% rate of protection against high‐grade squamous intraepithelial lesions (HSILs) or worse (HSIL+). Significant reductions in HPV16 (95%) and HPV18 (100%) infections were noted, but no differences were observed in HPV6 and HPV11 infections. The prevalences of HPV51 and HPV59 increased with vaccination, although these changes were not confirmed in the comparative study with J‐HERS 2011. Comparing the prevaccination (J‐HERS 2011) and postvaccination (J‐HERS 2021) periods, 43%, 51%, 88%, and 62% reductions in HPV16, HPV18, HPV16/18, and HPV31/58 infection rates were observed, respectively. Similarly, 62% and 71% reductions in LSIL/ASCH+ and HSIL+ rates were noted, respectively. There were 88% and 87% reductions in LSIL/ASCH+ and HSIL+ rates in 16–21‐ and 28–33‐year‐old patients, respectively. Bivalent or quadrivalent vaccines provided 100% protection against high‐grade squamous cell lesions (suggestive of CIN2 or CIN3) in young women aged <39 years at 9–12 years after initiation of Japan's first nationwide HPV vaccination program. Cross‐protection against HPV31 and HPV58 is likely to occur, although some HPV‐type replacements are inconsistent across vaccination regimens. This demonstrates the effectiveness of the HPV vaccine. However, continuous monitoring of cervical cancer and precancer is necessary in younger generations (born 1997–2007), who were rarely vaccinated due to the prolonged suspension of the vaccine recommendations in Japan.

The prevalence of VAIN, CIN, and related HPV genotypes in Japanese women with abnormal cytology

AbstractVaginal intraepithelial neoplasia (VAIN) is often found by chance. We investigated the prevalence of VAIN and related human papillomavirus (HPV) types in comparison with cervical intraepithelial neoplasia (CIN). This study enrolled 648 women who were referred to the outpatient clinic of Kanazawa Medical University Hospital for abnormal cytology from January 2009 to January 2019. HPV genotypes were determined using Genosearch‐31 + 4, which can detect 35 different HPV types. Colposcopy was performed at the first visit by an experienced gynecological oncologist. Among 611 subjects with squamous cell lesions, 107 (17.5%) VAIN cases were identified, and 67 (11.0%) women had both VAIN and CIN. Ultimately, 72 VAIN1, 15 VAIN2/3, 203 CIN1, 249 CIN2/3, 32 cervical squamous cell carcinomas (SCC), and one vaginal SCC (Vag‐SCC) were identified. The prevalences of VAIN1, VAIN2/3, and Vag‐SCC were 35.5%, 6.0%, and 3.1% of equivalent cervical lesions, respectively. The VAIN patients were older than the CIN patients (P = .002). About half of the VAIN cases were diagnosed during the follow‐up. Multiple HPV infections were found in 42.9% of the VAIN and CIN patients. HPV52, 16, 51, 53, and 56 were the most common types in VAIN, whereas HPV16, 52, 58, 51, and 31 predominated in CIN. HPV18 was rare in VAIN, HPV58 was more common in CIN than in VAIN, and HPV53 and HPV73 were more common in VAIN. In conclusion, VAIN1 was identified more frequently than we expected. Various HPV types were identified in the vagina, which is likely a reservoir for HPV.

Comparison of Aptima and hybrid capture‐2 HPV tests and Pap test in the referral population in Japan

AbstractThe Aptima human papillomavirus (HPV) test (APTIMA) detects E6‐E7 mRNA in abnormal cells in the uterine cervix. To investigate the accuracy of APTIMA for cervical cancer screening in Japan, 423 subjects, mostly referrals with abnormal cytology or being followed up for cervical intraepithelial neoplasia (CIN)1, were screened using two HPV tests, hybrid capture 2 (HC2) and APTIMA, and by the Pap test. Colposcopy was conducted in all subjects with a positive result in either test type. HPV genotyping was performed by Genosearch‐31.A result of atypical squamous cells‐undetermined significance (ASC‐US) or worse on the HC2 test (ASC‐US‐HC2), and low‐grade squamous intraepithelial lesion (LSIL) or worse (LSIL+) on the Pap test, was regarded as positive. APTIMA (97.5%) was more sensitive than LSIL+ (85.1%) for detecting CIN2 or worse (CIN2+) (McNemar test; p = .0003), and more sensitive (98.6%) than ASC‐US‐HC2 (92.7%) for detecting CIN3+. APTIMA and HC2 had similar sensitivities. HPV genotyping revealed that CIN2/3 with high‐risk HPV (HR‐HPV) was overlooked in five cases by ASC‐US‐HC2, and in four cases by HC2, while no such lesions were missed by APTIMA. Thus, APTIMA might be superior to HC2 for primary HPV screening in Japan. One cancer case positive for HPV67 (potentially high risk, [pHR]) was overlooked by Pap test and both HPV tests, suggesting a need for a new HPV test able to detect pHR‐HPV types.

Determination of human papillomavirus type in archival tissue specimens of invasive cervical cancer using molecular mapping and E6/E7-based polymerase chain reaction

In our previous study, an L1-based human papillomavirus (HPV) test using liquid-based cytology revealed that some invasive cervical cancers (ICC) exhibited multiple HPV types or harbored no HPV DNA. Here, molecular mapping of formalin-fixed paraffin-embedded cancer tissue specimens from the same patients were conducted to confirm these observations. Among 377 ICC cases, 73 eligible specimens (9 positive for multiple HPV types, 16 negative for HPV, and 48 positive for a single HPV type from the previous study) were reexamined by manual microdissection of cancer lesions, then subjected to HPV genotyping using the uniplex E6/E7 polymerase-chain-reaction method to detect all high-risk and potentially high-risk HPV types. The HPV typing results were confirmed in 52 of 73 cancer cases; among the 21 remaining cases, 15 were discordant and 6 were partially concordant. In total, 8 of 16 (50%) HPV-negative samples became positive; 6 were positive for HPV16 and 2 were positive for HPV67. Moreover, two samples previously positive for HPV6 and HPV53 were negative for HPV. All nine cancers with multiple HPV types were found to harbor only a single HPV type. In total, 63 cancer tissues exhibited a single HPV type. HPV16 and HPV18 were detected in squamous cell carcinoma (SCC) and adenocarcinoma (ADC). Alpha-5 (HPV82), -6 (HPV56), and -9 (HPV31/52/67) HPV types were detected in SCC, whereas Alpha-7 (HPV59/68) types were detected in ADC and adenosquamous carcinoma (ADSCC). These findings suggested that the different HPV types induced different histological cancers. Furthermore, all SCCs and 10 of 11 usual-type ADCs were positive for high-risk HPV types, supporting the use of HPV screening for the detection of these cancers and associated premalignant lesions. HPV16 is likely to remain undetected in some cervical cancer tissues because of low viral-copy-numbers. Putative high-risk HPV types (e.g., HPV67 and HPV82) might be high risk in Japan.