Allelic loss of HLA class I facilitates evasion from immune surveillance in cervical intraepithelial neoplasia.

Loss of heterozygosity (LOH) has been reported to occur in HLA regions in cervical intraepithelial neoplasia (CIN) and cervical cancer. However, the details of how this is related to the progression of CIN have been unclear. In this study, we examined the human papillomavirus (HPV) antigen-presenting capacity of people with CIN and the significance of LOH of HLA class I in the progression of CIN. It was shown that differences in antigen-presenting capacity among each case depended on HLA types, not HPV genotypes. Focusing on the HLA type, there was a positive correlation between antigen-presenting capacity against HPV and the frequency of allelic loss. Furthermore, the lost HLA-B alleles had a higher HPV antigen-presenting capacity than intact alleles. In addition, frequency of LOH of HLA class I was significantly higher in advanced CIN (CIN2-3) than in cervicitis or early-stage CIN (CIN1): around half of CIN2-3 had LOH of any HLA class I. Moreover, the antigen-presenting capacity against E5, which is the HPV proteins that facilitate viral escape from this immune surveillance by suppressing HLA class I expression, had the most significant impact on the LOH in HLA-B. This study suggests that HPV evades immune surveillance mechanisms when host cells lose the capacity for antigen presentation by HLA class I molecules, resulting in long-term infection and progression to advanced lesions.

Differential requirement of the transcription factor HOXC13 for the stable maintenance of human papillomavirus genome among high-risk genotypes.

The viral genome of the high-risk human papillomavirus (HPV), the causative agent of cervical cancer, is stably maintained as extrachromosomal episomes that establish persistent infection. We previously identified homeobox-transcription factor HOXC13 as an important host protein mediating the short-term retention of the HPV16 and HPV18 genomes in normal human immortalized keratinocytes (NIKS). Here, we used CRISPR-Cas9 technology to construct HOXC13 knockout (KO) NIKS cells to determine whether HOXC13 is required for the long-term maintenance of high-risk HPV genomes. HPV16, HPV18, HPV52, and HPV58 whole genomes were transfected into HOXC13 KO cells, and the copy number of viral genomes per cell was monitored over cell passages. Copy numbers of HPV16, HPV52, and HPV58 genomes decreased continuously in HOXC13 KO cells, whereas HPV18 genomes remained stable throughout passages. Thus, HOXC13 is critical for the stable maintenance of the viral genomes of HPV16, HPV52, and HPV58, but not HPV18.

Performance of an ancillary test for cervical cancer that measures miRNAs and cytokines in serum and cervical mucus.

Currently, human papillomavirus tests and cytology are used to screen for cervical cancer. However, more accurate ancillary screening tests are needed. MicroRNAs (miRNAs) and cytokines are promising biomarkers that are aberrantly expressed in cervical cancer. Therefore, the potential of developing new screening markers based on the levels of miRNAs and cytokines in serum and local mucus samples from the same patients with cervical neoplasia was investigated. miRNA screening was performed by microarray and measurement using real-time reverse-transcriptase PCR. Cytokine were measured using multiplex bead assay, and changes in expressions were analyzed based on disease severity. As lesions progressed, miR-20b-5p, -155-5p, -144-3p, -451a, and -126-3p expression levels were increased in mucus, and miR-16-5p, -223-3p, and -451a expression levels were decreased in serum. Regarding cytokines, IL-6, IL-8, monocyte chemoattractant protein-1, Eotaxin, interferon-γ, and RANTES were increased, whereas granulocyte-colony-stimulating factor (G-CSF) was significantly decreased in mucus. miRNAs and cytokines in serum did not have high diagnostic accuracy. However, a combination of miR-20b-5p, -451a, -126-3p, Eotaxin, as well as G-CSF in mucus samples, had high diagnostic accuracy with an area under the receiver operating characteristic curve of 0.989 (0.979-0.999). Our results suggest that using mucus for this ancillary test is more beneficial than serum.

A prospective clinical trial of diathermy ablation for patients with high-grade cervical intraepithelial neoplasia from a single institution in Japan.

Approximately 500,000 women are diagnosed with cervical cancer annually, with high-grade cervical intraepithelial neoplasia (CIN) estimated to be 20 times higher. The diathermy ablation is an inexpensive minimally invasive surgeries for CIN. However, little is known about the treatment outcomes. A prospective clinical trial was therefore conducted to evaluate ablation outcomes based on detailed colposcopy findings, cytology, and biopsy results over a two-year period. We enrolled CIN2 (n = 32) and CIN3 (n = 7) patients. Eligibility criteria included: aged between 29 and 49 (median: 36, mean: 36.3), visible transformation zone with high-grade lesions not entirely occupying the cervix, and histologically diagnosed with CIN2 or CIN3. Cytology and HPV genotyping were performed, and colposcopic findings were evaluated. Colposcopy-guided diathermy ablation was conducted by a certified gynecologic oncologist. The incidence of recurrent or residual disease was 5.1% (2/39, 95% confidence interval: - 0.02 to 0.12). The prevalence of HPV infection at 12 months decreased after surgery, as 67.6% (23/34, 0.52-0.83) of patients were HPV-negative. No severe adverse events were reported, while there were five pregnancies with full-term deliveries. The promising outcome was possibly due to selection of rigorous surgical indication and skilled surgical techniques. The study highlights the importance of experienced and skilled colposcopists.TrialRegistry This study was registered in the clinical trial registration system of the University hospital Medical Information Network Clinical Trials Registry (UMIN-CTR ID: UMIN000024483). Open for the trial to the public through the website: 01/11/2016. First registration of the patient: 30/01/2017.

Intra-Patient Genomic Variations of Human Papillomavirus Type 31 in Cervical Cancer and Precancer.

Human papillomavirus type 31 (HPV31) is detected less frequently in cervical cancer than two major causative types, HPV16 and HPV18. Here, we report a comprehensive analysis of HPV31 genome sequences in cervical lesions collected from Japanese women. Of 52 HPV31-positive cervical specimens analyzed by deep sequencing, 43 samples yielded complete genome sequences of around 7900 base pairs and 9 samples yielded partially deleted genome sequences. Phylogenetic analysis showed that HPV31 variant distribution was lineage A in 19 samples (36.5%), lineage B in 28 samples (53.8%), and lineage C in 5 samples (9.6%), indicating that lineage B variants are dominant among HPV31 infections in Japan. Deletions in the viral genome were found in the region from the E1 to L1 genes, but all the deleted genomes retained the E6/E7 genes. Among intra-patient nucleotide variations relative to a consensus genome sequence in each sample, C-to-T substitutions were most frequently detected, followed by T-to-C and C-to-A substitutions. High-frequency, intra-patient mutations (>10%) in cervical cancer samples were found in the E1, E2, and E7 genes, and all of them were nonsynonymous substitutions. The enrichment of high-frequency nonsynonymous substitutions strongly suggests that these intra-patient mutations are positively selected during the development of cervical cancer/precancer.

Human papillomavirus vaccine impact on invasive cervical cancer in Japan: Preliminary results from cancer statistics and the MINT study.

The first prophylactic vaccine against human papillomavirus (HPV) 16 and HPV18 was licensed in Japan in 2009. HPV vaccine effectiveness against high-grade cervical lesions has been demonstrated among young Japanese women, but evidence of its effects on invasive cervical cancer (ICC) is lacking. Using data from two different cancer registries, we compared recent trends of new ICC cases by age group using Poisson regression analysis. We also analyzed time trends in HPV16/18 prevalence among 1414 Japanese women aged <40 years newly diagnosed with ICC in the past decade. Based on the population-based cancer registry, the incidence of ICC among young women aged 20-29 years showed a significant decline from 3.6 to 2.8 per 100 000 women-years during 2016-2019, but no similar decline was observed for older age groups (p < 0.01). Similarly, using data from the gynecological cancer registry of the Japan Society of Obstetrics and Gynecology, the annual number of ICCs among women aged 20-29 years also decreased from 256 cases to 135 cases during 2011-2020 (p < 0.0001). Furthermore, a declining trend in HPV16/18 prevalence in ICC was observed only among women aged 20-29 years during 2017-2022 (90.5%-64.7%, p = 0.05; Cochran-Armitage trend test). This is the first report to suggest population-level effects of HPV vaccination on ICC in Japan. Although the declining trend in HPV16/18 prevalence among young women with ICC supports a causal linkage between vaccination and results from cancer registries, further studies are warranted to confirm that our findings are attributable to vaccination.

Nuclear proinflammatory cytokine S100A9 enhances expression of human papillomavirus oncogenes via transcription factor TEAD1.

Transcription of the human papillomavirus (HPV) oncogenes, E6 and E7, is regulated by the long control region (LCR) of the viral genome. Although various transcription factors have been reported to bind to the LCR, little is known about the transcriptional cofactors that modulate HPV oncogene expression in association with these transcription factors. Here, we performed in vitro DNA-pulldown purification of nuclear proteins in cervical cancer cells, followed by proteomic analyses to identify transcriptional cofactors that bind to the HPV16 LCR via the transcription factor TEAD1. We detected the proinflammatory cytokine S100A9 that localized to the nucleus of cervical cancer cells and associated with the LCR via direct interaction with TEAD1. Nuclear S100A9 levels and its association with the LCR were increased in cervical cancer cells by treatment with a proinflammatory phorbol ester. Knockdown of S100A9 decreased HPV oncogene expression and reduced the growth of cervical cancer cells and their susceptibility to cisplatin, whereas forced nuclear expression of S100A9 using nuclear localization signals exerted opposite effects. Thus, we conclude that nuclear S100A9 binds to the HPV LCR via TEAD1 and enhances viral oncogene expression by acting as a transcriptional coactivator. IMPORTANCE Human papillomavirus (HPV) infection is the primary cause of cervical cancer, and the viral oncogenes E6 and E7 play crucial roles in carcinogenesis. Although cervical inflammation contributes to the development of cervical cancer, the molecular mechanisms underlying the role of these inflammatory responses in HPV carcinogenesis are not fully understood. Our study shows that S100A9, a proinflammatory cytokine, is induced in the nucleus of cervical cancer cells by inflammatory stimuli, and it enhances HPV oncogene expression by acting as a transcriptional coactivator of TEAD1. These findings provide new molecular insights into the relationship between inflammation and viral carcinogenesis.

Folliculin Prevents Lysosomal Degradation of Human Papillomavirus To Support Infectious Cell Entry.

Human papillomavirus (HPV) infects epithelial basal cells in the mucosa and either proliferates with the differentiation of the basal cells or persists in them. Multiple host factors are required to support the HPV life cycle; however, the molecular mechanisms involved in cell entry are not yet fully understood. In this study, we performed a genome-wide clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein 9 (Cas9) knockout (KO) screen in HeLa cells and identified folliculin (FLCN), a GTPase-activating protein for Rag GTPases, as an important host factor for HPV infection. The introduction of single guide RNAs for the FLCN gene into HeLa, HaCaT, and ectocervical Ect1 cells reduced infection by HPV18 pseudovirions (18PsVs) and 16PsVs. FLCN KO HeLa cells also exhibited strong resistance to infection with 18PsVs and 16PsVs; nevertheless, they remained highly susceptible to infections with vesicular stomatitis virus glycoprotein-pseudotyped lentivirus and adeno-associated virus. Immunofluorescence microscopy revealed that the numbers of virions binding to the cell surface were slightly increased in FLCN KO cells. However, virion internalization analysis showed that the internalized virions were rapidly degraded in FLCN KO cells. This degradation was blocked by treatment with the lysosome inhibitor bafilomycin A1. Furthermore, the virion degradation phenotype was also observed in Ras-related GTP-binding protein C (RagC) KO cells. These results suggest that FLCN prevents the lysosomal degradation of incoming HPV virions by enhancing lysosomal RagC activity. IMPORTANCE Cell entry by human papillomavirus (HPV) involves a cellular retrograde transport pathway from the endosome to the trans-Golgi network/Golgi apparatus. However, the mechanism by which this viral trafficking is safeguarded is poorly understood. This is the first study showing that the GTPase-activating protein folliculin (FLCN) protects incoming HPV virions from lysosomal degradation and supports infectious cell entry by activating the Rag GTPases, presumably through the suppression of excessive lysosomal biosynthesis. These findings provide new insights into the effects of small GTPase activity regulation on HPV cell entry and enhance our understanding of the HPV degradation pathway.

Application of organoid culture from HPV18-positive small cell carcinoma of the uterine cervix for precision medicine.

BACKGROUND: Small cell carcinoma of the uterine cervix (SCCC) is a rare and highly malignant human papillomavirus (HPV)-associated cancer in which human genes related to the integration site can serve as a target for precision medicine. The aim of our study was to establish a workflow for precision medicine of HPV-associated cancer using patient-derived organoid. METHODS: Organoid was established from the biopsy of a patient diagnosed with HPV18-positive SCCC. Therapeutic targets were identified by whole exome sequencing (WES) and RNA-seq analysis. Drug sensitivity testing was performed using organoids and organoid-derived mouse xenograft model. RESULTS: WES revealed that both the original tumor and organoid had 19 somatic variants in common, including the KRAS p.G12D pathogenic variant. Meanwhile, RNA-seq revealed that HPV18 was integrated into chromosome 8 at 8q24.21 with increased expression of the proto-oncogene MYC. Drug sensitivity testing revealed that a KRAS pathway inhibitor exerted strong anti-cancer effects on the SCCC organoid compared to a MYC inhibitor, which were also confirmed in the xenograft model. CONCLUSION: In this study, we confirmed two strategies for identifying therapeutic targets of HPV-derived SCCC, WES for identifying pathogenic variants and RNA sequencing for identifying HPV integration sites. Organoid culture is an effective tool for unveiling the oncogenic process of rare tumors and can be a breakthrough for the development of precision medicine for patients with HPV-positive SCCC.

Evaluation of CD4+ cells infiltration as a prognostic factor in cervical intraepithelial neoplasia 2.

OBJECTIVE: To identify candidate predictors for the prognosis of cervical intraepithelial neoplasia 2 (CIN2) lesions and evaluate the prognostic value of the local immune response. METHODS: One hundred fifteen CIN2 patients were enrolled. The percentage of p16-, minichromosome maintenance complex component 2- or apolipoprotein B mRNA editing enzyme catalytic subunit 3G (APOBEC3G)-positive cells was determined immunohistochemically. Tumor-infiltrating lymphocytes (TILs) in intertumoral lesions were scored using an automated system. CIN3 disease progression and regression rates were estimated by the Kaplan-Meier method. A case-control study was conducted to screen CIN2 prognostic factors in 10 regression and 10 progression patients. Selected factors were examined in a cohort study to determine their prognostic value for CIN2. RESULTS: Among all participants, the cumulative progression and regression rates at 60 months were 0.477 and 0.510, respectively. In the case-control study, p16- and APOBEC3G-positive cells were higher in the progression group (p=0.043, p=0.023). Additionally, CD4+ cell infiltration was enhanced in the regression group (p=0.023). The cohort study revealed a significantly increased progression rate in patients with elevated p16-positive cells (p<0.001), and increased CD4+ TIL infiltration was associated with better regression (p=0.011). Kaplan-Meier analysis according to human papillomavirus (HPV) positivity revealed a greater CIN3 development risk in HPV16-positive patients than in HPV16-negative cases. Finally, multivariate analysis identified HPV16 infection and CD4+ TIL infiltration as independent prognostic factors in CIN2 regression. CONCLUSION: CD4+ TIL infiltration in intertumoral lesions was related with CIN2 regression. Our findings suggest CD4+ TIL infiltration may be useful for the triage of CIN2 patients.

Whole-genome analysis of human papillomavirus 67 isolated from Japanese women with cervical lesions.

BACKGROUND: Human papillomavirus (HPV) type 67 is phylogenetically classified into Alphapapillomavirus species 9 (alpha-9) together with other carcinogenic types (HPV16, 31, 33, 35, 52 and 58), but is the only alpha-9 type defined as possibly carcinogenic. This study aimed to determine whole-genome sequences of HPV67 isolated from Japanese women with cervical cancer or cervical intraepithelial neoplasia (CIN) to better understand the genetic basis of the oncogenic potential of HPV67. METHODS: Total cellular DNA isolated from cervical exfoliated cells that were single positive for HPV67 (invasive cervical cancer, n = 2; CIN3, n = 6; CIN 2, n = 1; CIN1, n = 2; the normal cervix, n = 1) was subjected to PCR to amplify HPV67 DNA, followed by next generation sequencing to determine the complete viral genome sequences. Variant lineages/sublineages were assigned through viral whole-genome phylogenetic analysis. The transcriptional activity of the virus early promoter was assessed by luciferase reporter assays in cervical cancer cell lines. RESULTS: Phylogenetic analyses of HPV67 genomes from Japan (n = 12) revealed that 11 belonged to lineage A (sublineage A1, n = 9; sublineage A2, n = 2) and one belonged to lineage B. All cancer cases contained sublineage A1 variants, and one of these contained an in-frame deletion in the E2 gene. The long control region of the HPV67 genome did not induce transcription from the virus early promoter in HeLa cells, but showed weak transcriptional activity in CaSki cells. CONCLUSIONS: The single detection of HPV67 in cervical cancer and precancer specimens strongly suggests the carcinogenic potential of this rare genotype. The phylogenetic analysis indicates a predominance of lineage A variants among HPV67 infections in Japan. Since only 23 complete genome sequences of HPV67 had been obtained until now, the newly determined genome sequences in this study are expected to contribute to further functional and evolutionary studies on the genetic diversity of HPV67.

Nomogram for predicted probability of cervical cancer and its precursor lesions using miRNA in cervical mucus, HPV genotype and age.

Cervical cancer is the fourth most common cancer in women worldwide. Although cytology or HPV testing is available for screening, these techniques have their drawbacks and optimal screening methods are still being developed. Here, we sought to determine whether aberrant expression of miRNAs in cervical mucus could be an ancillary test for cervical neoplasms. The presence of miRNAs in 583 and 126 patients (validation and external cohorts) was determined by real-time RT-PCR. Performance of a combination with five miRNAs (miR-126-3p, -451a -144-3p, -20b-5p and -155-5p) was estimated by ROC curve analysis. Predicted probability (PP) was estimated by nomograms comprising -ΔCt values of the miRNAs, HPV genotype and age. A combination of five miRNAs showed a maximum AUC of 0.956 (95% CI: 0.933-0.980) for discriminating cancer. Low PP scores were associated with good prognosis over the 2-year observation period (p < 0.05). Accuracy for identifying cancer and cervical intraepithelial neoplasia (CIN) 3 + by nomogram was 0.983 and 0.966, respectively. PP was constant with different storage conditions of materials. We conclude that nomograms using miRNAs in mucus, HPV genotype and age could be useful as ancillary screening tests for cervical neoplasia.

Regional differences in human papillomavirus type 52 prevalence among Japanese women with cervical intraepithelial neoplasia†.

Although geographical differences in the distribution of human papillomavirus genotypes have been observed worldwide, no studies have reported on national differences in the prevalence of human papillomavirus types in Japan. Here, we report a cross-sectional study to explore regional differences in the prevalence of human papillomavirus types among Japanese women with cervical intraepithelial neoplasia or invasive cervical cancer. Using human papillomavirus genotyping data from the nationwide prospective study on human papillomavirus vaccine effectiveness, we compared the frequency of detection of 15 high-risk and two low-risk human papillomavirus types in each disease category between the women who visited hospitals located in eastern Japan and those who visited hospitals located in western Japan. The risk of cervical intraepithelial neoplasia progression was assessed by calculating a prevalence ratio of each human papillomavirus type for cervical intraepithelial neoplasia grade 2/3 versus grade 1. Among the human papillomavirus types studied, human papillomavirus 52 was detected significantly more frequently in western hospitals than in eastern hospitals in cervical intraepithelial neoplasia grade 1 patients, but was less frequent in cervical intraepithelial neoplasia grade 2/3. The prevalence of particular human papillomavirus types was not significantly different between patients in hospitals in eastern Japan and those in hospitals in western Japan for invasive cervical cancer. In both eastern and western hospitals, a higher risk of cervical intraepithelial neoplasia progression was observed in patients infected with human papillomavirus 16, 31 or 58. In contrast, there was a significantly higher prevalence of human papillomavirus 52 infection in women with cervical intraepithelial neoplasia grade 2/3 than in those with cervical intraepithelial neoplasia grade 1 in eastern hospitals (prevalence ratio, 1.93; 95% confidence interval, 1.48-2.58), but not in western hospitals (prevalence ratio, 1.03; 95% confidence interval, 0.83-1.30). Regional differences of human papillomavirus 52 prevalence in cervical intraepithelial neoplasia lesions may exist and emphasize the importance of continuous monitoring of human papillomavirus type prevalence throughout the country in order to accurately assess the efficacy of human papillomavirus vaccines.

Ancient Evolutionary History of Human Papillomavirus Type 16, 18 and 58 Variants Prevalent Exclusively in Japan.

Human papillomavirus (HPV) is a sexually transmitted virus with an approximately 8-kilo base DNA genome, which establishes long-term persistent infection in anogenital tissues. High levels of genetic variations, including viral genotypes and intra-type variants, have been described for HPV genomes, together with geographical differences in the distribution of genotypes and variants. Here, by employing a maximum likelihood method, we performed phylogenetic analyses of the complete genome sequences of HPV16, HPV18 and HPV58 available from GenBank (n = 627, 146 and 157, respectively). We found several characteristic clusters that exclusively contain HPV genomes from Japan: two for HPV16 (sublineages A4 and A5), one for HPV18 (sublineage A1) and two for HPV58 (sublineages A1 and A2). Bayesian phylogenetic analyses of concatenated viral gene sequences showed that divergence of the most recent common ancestor of these Japan-specific clades was estimated to have occurred ~98,000 years before present (YBP) for HPV16 A4, ~39,000 YBP for HPV16 A5, ~38,000 YBP for HPV18 A1, ~26,000 for HPV58 A1 and ~25,000 YBP for HPV58 A2. This estimated timeframe for the divergence of the Japan-specific clades suggests that the introduction of these HPV variants into the Japanese archipelago dates back to at least ~25,000 YBP and provides a scenario of virus co-migration with ancestral Japanese populations from continental Asia during the Upper Paleolithic period.

Changes in HPV16/18 Prevalence among Unvaccinated Women with Cervical Intraepithelial Neoplasia in Japan: Assessment of Herd Effects following the HPV Vaccination Program.

Since the human papillomavirus (HPV) vaccination program for Japanese girls aged 12-16 years began in 2010, vaccination uptake has been low in women born before 1993 but high (approximately 70%) in those born during 1994-1999. We previously compared the prevalence of vaccine types HPV16 and HPV18 in cervical intraepithelial neoplasia grade 1-3 (CIN1-3) or adenocarcinoma in situ (AIS) between vaccinated and unvaccinated cohorts and found direct protection effects among vaccinated women in Japan. In this study, we focused on changes in HPV16/18 prevalence among "unvaccinated" cohorts with CIN/AIS. We analyzed HPV16/18 prevalence among 5051 unvaccinated women aged <40 years, newly diagnosed with CIN/AIS during 2012-2021 for time trends. Declining trends in HPV16/18 prevalence over 9 years were observed in CIN1 (36.0-10.0%, Ptrend = 0.03) and CIN2-3/AIS (62.5-36.4%, Ptrend = 0.07) among women aged <25 years. HPV16/18 prevalence in CIN1 and CIN2-3/AIS diagnosed at age 20-24 years was lower in 1994-1999 birth cohorts compared with 1988-1993 birth cohorts (4.5% vs. 25.7% for CIN1 and 40.0% vs. 58.1% for CIN2-3/AIS, both p = 0.04). Significant reduction in HPV16/18 prevalence among young unvaccinated women with CIN1 and CIN2-3/AIS suggests herd effects of HPV vaccination in Japan.

Human papillomavirus vaccine effectiveness by age at first vaccination among Japanese women.

In Japan, the National Immunization Program against human papillomavirus (HPV) targets girls aged 12-16 years, and catch-up vaccination is recommended for young women up to age 26 years. Because HPV infection rates increase soon after sexual debut, we evaluated HPV vaccine effectiveness by age at first vaccination. Along with vaccination history, HPV genotyping results from 5795 women younger than 40 years diagnosed with cervical intraepithelial neoplasia grade 2-3 (CIN2-3), adenocarcinoma in situ (AIS), or invasive cervical cancer were analyzed. The attribution of vaccine-targeted types HPV16 or HPV18 to CIN2-3/AIS was 47.0% for unvaccinated women (n = 4297), but 0.0%, 13.0%, 35.7%, and 39.6% for women vaccinated at ages 12-15 years (n = 36), 16-18 years (n = 23), 19-22 years (n = 14), and older than 22 years (n = 91), respectively, indicating the greater effectiveness of HPV vaccination among those initiating vaccination at age 18 years or younger (P < .001). This finding was supported by age at first sexual intercourse; among women with CIN2-3/AIS, only 9.2% were sexually active by age 14 years, but the percentage quickly increased to 47.2% by age 16 and 77.1% by age 18. Additionally, the HPV16/18 prevalence in CIN2-3/AIS was 0.0%, 12.5%, and 40.0% for women vaccinated before (n = 16), within 3 years (n = 8), and more than 3 years after (n = 15) first intercourse, respectively (P = .004). In conclusion, our data appear to support routine HPV vaccination for girls aged 12-14 years and catch-up vaccination for adolescents aged 18 years and younger in Japan.

IFN-γ‒Induced APOBEC3B Contributes to Merkel Cell Polyomavirus Genome Mutagenesis in Merkel Cell Carcinoma.

Merkel cell polyomavirus (MCPyV) is the causative agent of an aggressive skin tumor, Merkel cell carcinoma. The viral genome is integrated into the tumor genome and harbors nonsense mutations in the helicase domain of large T antigen. However, the molecular mechanisms by which the viral genome gains the tumor-specific mutations remain to be elucidated. Focusing on host cytosine deaminases APOBEC3s, we find that A3A, A3B, or A3G introduces A3-specific mutations into episomal MCPyV genomes in MCPyV-replicating 293-derivative cells. Sequence analysis of MCPyV genomes retrieved from the NCBI database revealed a decrease of TpC dinucleotide, a preferred target for A3A and A3B, in the 3'-region of the large T antigen‒coding sequence. The viral DNA isolated from tumors contained mutated cytosines, with a remarkable bias toward TpC dinucleotide. Analysis of publicly available microarray data showed that expression of IFN-γ and cytotoxic T lymphocyte markers was positively correlated with the A3A, A3B, and A3G levels in MCPyV-positive but not in MCPyV-negative tumors. Finally, IFN-γ treatment induced A3B and A3G expression in the MCPyV-positive Merkel cell carcinoma cell line MS-1. These results suggest that the IFN-γ-A3B axis plays pivotal roles in evolutionally shaping MCPyV genomic sequences and in generating tumor-specific large T antigen mutations during development of Merkel cell carcinoma.

Transcription Factor Homeobox D9 Drives the Malignant Phenotype of HPV18-Positive Cervical Cancer Cells via Binding to the Viral Early Promoter.

Persistent infections with two types of human papillomaviruses (HPV), HPV16 and HPV18, are the most common cause of cervical cancer (CC). Two viral early genes, E6 and E7, are associated with tumor development, and expressions of E6 and E7 are primarily regulated by a single viral promoter: P97 in HPV16 and P105 in HPV18. We previously demonstrated that the homeobox D9 (HOXD9) transcription factor is responsible for the malignancy of HPV16-positive CC cell lines via binding to the P97 promoter. Here, we investigated whether HOXD9 is also involved in the regulation of the P105 promoter using two HPV18-positive CC cell lines, SKG-I and HeLa. Following the HOXD9 knockdown, cell viability was significantly reduced, and E6 expression was suppressed and was accompanied by increased protein levels of P53, while mRNA levels of TP53 did not change. E7 expression was also downregulated and, while mRNA levels of RB1 and E2F were unchanged, mRNA levels of E2F-target genes, MCM2 and PCNA, were decreased, which indicates that the HOXD9 knockdown downregulates E7 expression, thus leading to an inactivation of E2F and the cell-cycle arrest. Chromatin immunoprecipitation and promoter reporter assays confirmed that HOXD9 is directly associated with the P105 promoter. Collectively, our results reveal that HOXD9 drives the HPV18 early promoter activity to promote proliferation and immortalization of the CC cells.

Comparison of prevalence of Felis catus papillomavirus type 2 in squamous cell carcinomas in cats between Taiwan and Japan.

Felis catus papillomavirus (FcaPV), especially type 2 (FcaPV2) is considered as one of the causative agents in squamous cell carcinoma (SCC) in cats. However, our previous study detected FcaPV3 and FcaPV4, but not FcaPV2 in feline SCCs collected in Japan, suggesting that the prevalence of FcaPV2 in SCC may vary depending on geographic locations. To evaluate this hypothesis, two conventional PCR reactions targeting E1 and E7 genes were performed to detect FcaPV2 in feline SCC samples collected in Taiwan and Japan. While 46.9% (23/49) of feline SCC cases from Taiwan were PCR positive for FcaPV2, only 8.6% (3/35) cases from Japan were positive. Our result suggests that the prevalence of FcaPV2 in feline SCCs may depend on the region.