Monitoring HPV Prevalence and Risk Cofactors for Abnormal Cytology in the Post-Vaccination Period among Croatian Women.

The incidence and mortality rate of cervical cancer in Croatia remains a health challenge despite screening efforts. Besides the persistent infection with HPV, the development of cancer is also associated with some cofactors. The goal of this study was to assess circulating HPV genotypes and risk factors for the development of cervical precancer after almost 16 years from the onset of HPV vaccination in Croatia. In this study, a total of 321 women attending gynecological care were evaluated. Relevant medical and demographic information, including cytology, were collected. HPV genotyping was performed by PCR. Comparing the HPV types found in circulation in the pre-vaccination (1999-2015) and post-vaccination periods (2020-2023), a statistically significant reduction in HPV 31 was noted, while the overall prevalence increased in the post-vaccination period. Besides the expected HPV positivity as a risk factor, the history of smoking was associated with LSIL or worse cytology at enrollment. For the first time, this population study revealed a statistically significant shift in the HPV genotype in the post-vaccination period, as well as the confirmation of risk factors for the development of abnormal cytology among Croatian women.

Integrative analysis in head and neck cancer reveals distinct role of miRNome and methylome as tumour epigenetic drivers.

Head and neck cancer is the sixth most common malignancy worldwide, with the relatively low 5-year survival rate, mainly because it is diagnosed at a late stage. Infection with HPV is a well known aetiology, which affects the nature of these cancers and patients' survival. Besides, it is considered that the main driving force for this type of cancer could be epigenetics. In this study we aimed to find potential epigenetic biomarkers, by integrating miRNome, methylome, and transcriptome analyses. From the fresh head and neck cancer tissue samples, we chose a group for miRNome, methylome and transcriptome profiling, in comparison to adequate control samples. Bioinformatics analyses are performed in R v4.2.2. Count normalisation and group differential expression for mRNA and the previously obtained miRNA count data was performed with DESeq2 v1.36. Gene set enrichment analysis was performed and visualised using gProfiler2 v0.2.1 Identification of miRNA targets was performed by querying in miRTarBase using multiMiR v1.18.0. Annotation of CpG sites merging into islands was obtained from RnBeads.hg19 v1.28.0. package. For the integrative analysis we performed kmeans clustering using stats v4.2.2 package, using 8-12 clusters and nstart 100. We found that transcriptome analysis divides samples into cancers and controls clusters, with no relation to HPV status or cancer anatomical location. Differentially expressed genes (n = 2781) were predominantly associated with signalling pathways of tumour progression. We identified a cluster of genes under the control of the transcription factor E2F that are significantly underexpressed in cancer tissue, as well as T cell immunity genes and genes related to regulation of transcription. Among overexpressed genes in tumours we found those that belong to cell cycle regulation and vasculature. A small number of genes were found significantly differentially expressed in HPV-positive versus HPV-negative tumours (for example NEFH, ZFR2, TAF7L, ZNF541, and TYMS). In this comprehensive study on an overlapping set of samples where the integration of miRNome, methylome and transcriptome analysis were performed for head and neck cancer, we demonstrated that the majority of genes were associated exclusively with miRNome or methylome and, to a lesser extent, under the control of both epigenetic mechanisms.

Methylation of Immune Gene Promoters in Oral and Oropharyngeal Cancer.

The proportion of oral and oropharyngeal squamous cell carcinoma (OOSCC) that can be attributed to human papillomavirus (HPV) infection is growing nowadays. A potential factor indicating the occurrence of HPV-positive OSCC is a change in the degree of methylation of gene promoters that play a key role in the immune response. In this study, we investigated the difference in the methylation of EDARADD, GBP4, HAVCR2, HLA DPB1, IL12RB1, MARCO, and SIGLEC12 gene promoters in samples of healthy oral mucosa versus samples of oral and oropharyngeal cancer. The presence of HPV infection in samples was examined earlier. To determine the difference in methylation of those gene promotors, isolated and bisulfite-modified DNA was analysed by the methylation-specific PCR method. The investigated gene promoters were found to be more hypomethylated in the oral and oropharyngeal cancer samples in comparison to normal tissue. The proportion of unmethylated gene promoters was similar in HPV-positive and HPV-negative cancers, although the data should be confirmed on a larger set of samples. To conclude, in samples of healthy oral mucosa, the investigated gene promoters were found to be methylated in a high percentage (73.3% to 100%), while in oral and oropharyngeal cancer samples, they were methylated in a low percentage (11.1% to 37%), regardless of HPV infection.

Head and Neck Cancer Patients' Survival According to HPV Status, miRNA Profiling, and Tumour Features-A Cohort Study.

Head and neck cancers (HNC) are a heterogeneous group of tumours mainly associated with tobacco and alcohol use and human papillomavirus (HPV). Over 90% of all HNC are squamous cell carcinomas (HNSCC). Sample material from patients diagnosed with primary HNSCC (n = 76) treated with surgery as primary treatment at a single centre were assessed for HPV genotype, miR-9-5p, miR-21-3p, miR-29a-3p and miR-100-5p expression levels. Clinical and pathological data were collected from medical records. Patients were enrolled between 2015 and 2019 and followed-up until November 2022. Overall survival, disease-specific survival and disease-free survival were assessed and correlated with clinical, pathological, and molecular data. Kaplan-Meier and Cox proportional hazard regression was used to assess different risk factors. In the study, male gender, HPV-negative HNSCC (76.3%) mostly located in the oral region (78.9%) predominated. Most patients had stage IV cancer (47.4%), and the overall survival rate was 50%. HPV was found not to affect survival, indicating that in this population, classic risk factors predominate. The presence of both perineural and angioinvasion was strongly associated with survival in all analyses. Of all miRNAs assessed, only upregulation of miR-21 was consistently shown to be an independent predictor of poor prognosis and may thus serve as a prognostic biomarker in HNSCC.

Human Papillomaviruses-Associated Cancers: An Update of Current Knowledge.

Human papillomaviruses (HPVs), which are small, double-stranded, circular DNA viruses infecting human epithelial cells, are associated with various benign and malignant lesions of mucosa and skin. Intensive research on the oncogenic potential of HPVs started in the 1970s and spread across Europe, including Croatia, and worldwide. Nowadays, the causative role of a subset of oncogenic or high-risk (HR) HPV types, led by HPV-16 and HPV-18, of different anogenital and head and neck cancers is well accepted. Two major viral oncoproteins, E6 and E7, are directly involved in the development of HPV-related malignancies by targeting synergistically various cellular pathways involved in the regulation of cell cycle control, apoptosis, and cell polarity control networks as well as host immune response. This review is aimed at describing the key elements in HPV-related carcinogenesis and the advances in cancer prevention with reference to past and on-going research in Croatia.

DNA Methylome Distinguishes Head and Neck Cancer from Potentially Malignant Oral Lesions and Healthy Oral Mucosa.

There is a strong need to find new, good biomarkers of head and neck squamous cell carcinoma (HNSCC) because of the bad prognoses and high mortality rates. The aim of this study was to identify the potential biomarkers in HNSCC that have differences in their DNA methylome and potentially premalignant oral lesions, in comparison to healthy oral mucosa. In this study, 32 oral samples were tested: nine healthy oral mucosae, 13 HNSCC, and 10 oral lesions for DNA methylation by the Infinium MethylationEPIC BeadChip. Our findings showed that a panel of genes significantly hypermethylated in their promoters or specific sites in HNSCC samples in comparison to healthy oral samples, which are mainly oncogenes, receptor, and transcription factor genes, or genes included in cell cycle, transformation, apoptosis, and autophagy. A group of hypomethylated genes in HNSCC, in comparison to healthy oral mucosa, are mainly involved in the host immune response and transcriptional regulation. The results also showed significant differences in gene methylation between HNSCC and potentially premalignant oral lesions, as well as differently methylated genes that discriminate between oral lesions and healthy mucosa. The given methylation panels point to novel potential biomarkers for early diagnostics of HNSCC, as well as potentially premalignant oral lesions.

Potential Novel Biomarkers in Chronic Graft-Versus-Host Disease.

Prognostic, diagnostic or predictive biomarkers are urgently needed for assessment of chronic graft-versus-host disease (cGvHD), a major risk for patients undergoing allogeneic hematopoietic stem cell transplantation. The main goal of this review generated within the COST Action EUROGRAFT "Integrated European Network on Chronic Graft Versus Host Disease" was to identify potential novel biomarkers for cGvHD besides the widely accepted molecular and cellular biomarkers. Thus, the focus was on cellular biomarkers, alloantibodies, glycomics, endothelial derived particles, extracellular vesicles, microbiome, epigenetic and neurologic changes in cGvHD patients. Both host-reactive antibodies in general, and particularly alloantibodies have been associated with cGvHD and require further consideration. Glycans attached to IgG modulate its activity and represent a promising predictive and/or stratification biomarker for cGVHD. Furthermore, epigenetic changes such as microRNAs and DNA methylation represent potential biomarkers for monitoring cGvHD patients and novel targets for developing new treatment approaches. Finally, the microbiome likely affects the pathophysiology of cGvHD; bacterial strains as well as microbial metabolites could display potential biomarkers for dysbiosis and risk for the development of cGvHD. In summary, although there are no validated biomarkers currently available for clinical use to better inform on the diagnosis, prognosis or prediction of outcome for cGvHD, many novel sources of potential markers have shown promise and warrant further investigation using well characterized, multi-center patient cohorts.

Genome-wide miRNA profiling reinforces the importance of miR-9 in human papillomavirus associated oral and oropharyngeal head and neck cancer.

Head and neck cancer is the sixth most common malignancy worldwide, predominantly developing from squamous cell epithelia (HNSCC). The main HNSCC risk factors are tobacco, excessive alcohol use, and the presence of human papillomavirus (HPV). HPV positive (+) cancers are etiologically different from other HNSCC and often show better prognosis. The current knowledge regarding HNSCC miRNA profiles is still incomplete especially in the context of HPV+ cancer. Thus, we analyzed 61 freshly collected primary oral (OSCC) and oropharyngeal (OPSCC) SCC samples. HPV DNA and RNA was found in 21% cases. The Illumina whole-genome small-RNA profiling by next-generation sequencing was done on 22 samples and revealed 7 specific miRNAs to HPV+ OSCC, 77 to HPV+ OPSCC, and additional 3 shared with both; 51 miRNAs were specific to HPV- OPSCC, 62 to HPV- OSCC, and 31 shared with both. The results for 9 miRNAs (miR-9, -21, -29a, -100, -106b, -143 and -145) were assessed by reverse transcription-quantitative polymerase chain reaction on the whole study population. The data was additionally confirmed by reanalyzing publicly available miRNA sequencing Cancer Genome Atlas consortium (TCGA) HNSCC data. Cell signaling pathway analysis revealed differences between HPV+ and HPV- HNSCC. Our findings compared with literature data revealed extensive heterogeneity of miRNA deregulation with only several miRNAs consistently affected, and miR-9 being the most likely HPV related miRNA.

Cervical HPV type-specific pre-vaccination prevalence and age distribution in Croatia.

The main etiological factor of precancerous lesion and invasive cervical cancer are oncogenic human papillomaviruses types (HPVs). The objective of this study was to establish the distribution of the most common HPVs in different cervical lesions and cancer prior to the implementation of organized population-based cervical screening and HPV vaccination in Croatia. In this study, 4,432 cervical specimens, collected through a 16-year period, were tested for the presence of HPV-DNA by polymerase chain reaction (PCR) with three sets of broad-spectrum primers and type-specific primers for most common low-risk (LR) types (HPV-6, 11) and the most common high-risk (HR) types (HPV-16, 18, 31, 33, 45, 52, 58). Additional 35 archival formalin-fixed, paraffin embedded tissue of cervical cancer specimens were analyzed using LiPA25 assay. The highest age-specific HPV-prevalence was in the group 18-24 years, which decreased continuously with age (P<0.0001) regardless of the cytological diagnosis. The prevalence of HR-HPV types significantly increased (P<0.0001) with the severity of cervical lesions. HPV-16 was the most common type found with a prevalence (with or without another HPV-type) of 6.9% in normal cytology, 15.5% in atypical squamous cells of undetermined significance, 14.4% in low-grade squamous intraepithelial lesions, 33.3% in high-grade squamous intraepithelial lesions, and 60.9% in cervical cancer specimens (P<0.0001). This study provides comprehensive and extensive data on the distribution of the most common HPV types among Croatian women, which will enable to predict and to monitor the impact of HPV-vaccination and to design effective screening strategies in Croatia.

Methylated Host Cell Gene Promoters and Human Papillomavirus Type 16 and 18 Predicting Cervical Lesions and Cancer.

Change in the host and/or human papillomavirus (HPV) DNA methylation profile is probably one of the main factors responsible for the malignant progression of cervical lesions to cancer. To investigate those changes we studied 173 cervical samples with different grades of cervical lesion, from normal to cervical cancer. The methylation status of nine cellular gene promoters, CCNA1, CDH1, C13ORF18, DAPK1, HIC1, RARß2, hTERT1, hTERT2 and TWIST1, was investigated by Methylation Specific Polymerase Chain Reaction (MSP). The methylation of HPV18 L1-gene was also investigated by MSP, while the methylated cytosines within four regions, L1, 5'LCR, enhancer, and promoter of the HPV16 genome covering 19 CpG sites were evaluated by bisulfite sequencing. Statistically significant methylation biomarkers distinguishing between cervical precursor lesions from normal cervix were primarily C13ORF18 and secondly CCNA1, and those distinguishing cervical cancer from normal or cervical precursor lesions were CCNA1, C13ORF18, hTERT1, hTERT2 and TWIST1. In addition, the methylation analysis of individual CpG sites of the HPV16 genome in different sample groups, notably the 7455 and 7694 sites, proved to be more important than the overall methylation frequency. The majority of HPV18 positive samples contained both methylated and unmethylated L1 gene, and samples with L1-gene methylated forms alone had better prognosis when correlated with the host cell gene promoters' methylation profiles. In conclusion, both cellular and viral methylation biomarkers should be used for monitoring cervical lesion progression to prevent invasive cervical cancer.

Epigenetic activation of immune genes in cervical cancer.

Immune system provides us protection from infectious pathogens and tumors formation during lifetime. Cervical cancer (CC), and its cause, human papillomavirus (HPV) are both challenges for the immune system. We present here evidence of epigenetic activation of immune system genes in CC. Illumina Infinium Human Methylation 450K BeadChip identified genes, which were all significantly hypomethylated in CC tissue versus normal tissue. The GeneMANIA computer program identified a tight network between those genes. The most strongly correlated genes based on their function are immune effectors' process (AIM2, BST2, BTN3A3, and IL12RB1) and response to virus related genes (AIM2, BST2, and IL12RB1). Thus, activation of those genes through demethylation is probably triggered by HPV oncogenes. In conclusion, the immune system of women who do not develop CC is probably activated earlier through DNA demethylation.

Genome-wide DNA methylation assay reveals novel candidate biomarker genes in cervical cancer.

The oncogenic human papilloma viruses (HPVs) are associated with precancerous cervical lesions and development of cervical cancer. The DNA methylation signatures of the host genome in normal, precancerous and cervical cancer tissue may indicate tissue-specific perturbation in carcinogenesis. The aim of this study was to identify new candidate genes that are differentially methylated in squamous cell carcinoma compared with DNA samples from cervical intraepithelial neoplasia grade 3 (CIN3) and normal cervical scrapes. The Illumina Infinium HumanMethylation450 BeadChip method identifies genome-wide DNA methylation changes in CpG islands, CpG shores and shelves. Our findings showed an extensive differential methylation signature in cervical cancer compared with the CIN3 or normal cervical tissues. The identified candidate biomarker genes for cervical cancer represent several types of mechanisms in the cellular machinery that are epigenetically deregulated by hypermethylation, such as membrane receptors, intracellular signaling and gene transcription. The results also confirm extensive hypomethylation of genes in the immune system in cancer tissues. These insights into the functional role of DNA methylome alterations in cervical cancer could be clinically applicable in diagnostics and prognostics, and may guide the development of new epigenetic therapies.

Advances in cervical cancer control and future perspectives.

The knowledge that the persistent infection with high-risk (HR) human papillomavirus (HPV) is the etiological factor in the development of cervical cancer has led to the development of the HPV DNA detection methods as well as the prophylactic vaccine against the most common HR-HPV types, HPV 16 and 18. Despite HPV vaccination, cervical cancer screening will remain the main preventive measure for both vaccinated and non-vaccinated women, but the nature of screening and management of women with cervical disease is being adapted to the new technologies. Although, HPV DNA detection is more sensitive that cytology, its specificity is lower, since most HPV infections are transient. Therefore, other methods are considered to improve the management of women with cervical disease. Typing of HPV DNA and viral load measurements are still used for research purposes only. Detection of viral oncogene E6/E7 transcripts, which is the marker of the productive infection, is a promising tool for follow-up of HPV DNA-positive women. The detection of p16INK4a over-expression, as an indirect test of E6/E7 expression, is used for confirmation of cervical neoplasia. Despite the lack of standardization, the detection of p16INK4a is useful in clinical settings, however its reproducibility in the management of low-grade and borderline cases is low. Future perspectives include the determination of the methylation status of several cellular genes that could predict the progression of the disease.

Detection and typing of human papillomaviruses combining different methods: polymerase chain reaction, restriction fragment length polymorphism, line probe assay and sequencing.

The identification of the etiological factor of many cervical precancerous lesions and cervical cancer, the human papillomavirus (HPV) is widely used. In this study, we evaluated the consensus and type-specific (TS) polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), line probe assay (LiPA, Innogenetics) and sequencing to determine the HPV types in cervical specimens. Out of 690 High-grade Squamous Intraepithelial Lesion (HSIL) samples, 86.7% were HPV positive and 13.3% HPV negative by consensus primers (MY09/MY11, L1C1/L1C2-1/L1C2-2 and/or GP5/6) directed PCR. Out of 598 HPV positive samples, 85.3% were typed by TS-PCR being HPV 6/11, 16, 18, 31 and/or 33, while 14.7% remained untyped. The most prevalent HPV type in the study group was HPV 16, identified in 35.5% cases, while HPV 31 was the second most frequent HPV type with a prevalence of 10.5%. They were followed by HPV types 6/11, 33 and 18 with a prevalence of 7.4%, 6.2% and 4.9%, respectively. Multiple HPV infections with two or more HPV types (6/11, 16, 18, 31 and/or 33) were found in 9.4% cases. A subset of 88 samples was further typed by RFLP and LiPA to determine the rare HPV types in HSIL samples. The most frequent low abundant HPV types in single infections in decreasing order were HPV 53, 58, 66, 56 and 52, while HPV 51 was the most frequent low abundant HPV type found in multiple HPV infections. Multiple HPV infections were mostly found by LiPA in 27.3% cases versus 14.8% cases found by RFLP. The perfect agreement between RFLP and LiPA assay pair was observed only for HPV types 16, 18, 34 and 59 (kappa value of 1). For other HPV types, the inter-assay agreement ranged from very good to no agreement indicating that neither assay is perfect. Sequencing was performed for 33 samples in cases where both RFLP and LiPA were inconclusive. Sequencing was shown to be a very good method in case of single HPV infection but not applicable in case of multiple HPV infections. Both RFLP and LiPA are good assays for epidemiological studies, although RFLP being cumbersome and time-consuming is less applicable than LiPA. Careful consideration has to be made before the implementation of either HPV typing methods in clinical laboratories.

Retrospective study of the prevalence of high-risk human papillomaviruses among Croatian women.

The infection with Human papillomavirus (HPV) is the necessary cause for cervical cancer. There are at least 15 High-Risk (HR) HPV types that are significantly associated with progression of cervical intraepithelial neoplasia to cervical cancer. Since previous studies showed that the prevalence of HPV in cervical cancers varies among different geographic regions, we wanted to investigate the prevalence of HPV types in Croatia, especially low abundant HR HPV types. By means of consensus primers directed polymerase chain reaction (PCR), we analysed cervical DNA samples of 2,136 Croatian women, mostly with abnormal cervical smears, in order to detect the presence of HPV Type-specific primers were then used to determine Low-Risk (LR) HPV types 6/11 and HR HPV types 16, 18, 31, 33, 45, 52 and 58. Out of 2,136 specimens, 1,255 (58.8%) were positive for HPV More than half of positive samples were typed (64.5%) and 35.5% still remained untyped. Multiple HPV infections were found in 10.3% of the cases. The most prevalent type, including both single and multiple infections, was HPV16 with the prevalence of 15.9%, followed by HPV types 31, 6/11, 33, 18, 52, 45 and 58 with 8.7%, 7.1%, 4.5%, 3.8%, 2.3%, 1.2% and 1.1%, respectively. The significant increase of frequency from Low-grade Squamous Intraepithelial Lesions (LSIL) to High-grade Squamous Intraepithelial Lesions (HSIL) was observed for HR HPV types 16, 18, 31 and 33 but not 45, 52 and 58. The frequency of unknown HPV types was almost the same in cervical specimens of women with LSIL and those with HSIL, 19.8% and 21.1%, respectively. The prevalence of HPV infection rate decreased significantly with patient age from 68.5% (age group 12 to 24 years) to 38.8% (age group 45 to 54 years). But, in women aged 55 or older the overall prevalence increased to 56.6%. Our results indicate that prevalence of HR HPV types in Croatia is similar to other countries. We suggest that HPV positive women in Croatia should be closely monitored by typing for HR HPV types: 16, 18, 31, 33, 45, 52 and 58.