Correlation between vaginal microbiota and different progression stages of cervical cancer

The Interplay Between Cervicovaginal Microbiota Diversity, Lactobacillus Profiles and Human Papillomavirus in Cervical Cancer: A Systematic Review

Background and Objectives: Interest in defining the characteristics of the cervicovaginal microbiota (CVM) in invasive cervical cancer (ICC) is growing, particularly concerning Lactobacillus species, as evidence suggests that these may differ in affected women and potentially interact with Human Papillomavirus (HPV) infection. Understanding these features could have important implications for disease management. Thus, this study aims to systematically review the main characteristics of available literature exploring the relationship between CVM diversity, Lactobacillus profiles, and HPV in ICC; Methods: A comprehensive bibliographic search was conducted across databases, including Medline, Embase, Scopus, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov, in accordance with the to the PRISMA guidelines. The review included studies that met the following inclusion criteria: studies comparing CVM in women with ICC to controls, focusing on Community State Types (CSTs), Lactobacillus profiles, and microbial diversity. Exclusion criteria included commentaries, letters, reviews, and studies without control groups. Variables were analyzed using the Kruskal-Wallis and Fisher's exact tests, with statistical significance level set at 0.05. Data analysis was conducted and reviewed in a blinded manner. Results: A total of 28 studies published between 2015 and 2024 met the inclusion criteria. A total of 2082 patients were included, with 323 (41.9%) of the 770 cases testing positive for HPV and 327 (24.9%) of the 1312 controls testing positive for HPV. A total of 18 studies specifically examined HPV genotypes. Cervical swabs were employed in 19 out of 28 studies (67.9%), while vaginal swabs were used in 17 studies (60.7%). Additionally, two studies included samples collected via cervical biopsy (7.1%), four studies utilized cervicovaginal lavage (14.3%), and one study used a cervical brush for sample collection (3.6%). Regarding microbiota profiling, 26 studies (92.9%) employed 16S rRNA analysis, while one study (3.6%) utilized whole-genome sequencing (WGS), and another (3.6%) used 16s rDNA. A total of 10 studies (35.7%) examined the distribution of CSTs. Five studies (17.9%) reported on Lactobacillus profiles. Different levels of Lactobacillus crispatus and Lactobacillus iners were observed, along with variations between Lactobacillus-dominant and Lactobacillus-depleted communities. A total of 22 studies (78.6%) assessed α-diversity, and 17 studies (60.7%) examined β-diversity; Conclusions: This study emphasizes the heterogeneous features of the studies exploring the association between alterations in the CVM, HPV, and the development of ICC, suggesting the need for further research to better understand this relationship. These findings could inform new strategies for prevention and treatment.

Nanoparticles and the Vaginal Microbiota: Diagnostic and Therapeutic Innovations in Human Papilloma Virus-associated Cervical Cancer - A Systematic Review

Cervical cancer (CC) remains a significant global health challenge, with the interplay between microbiome and cancer progression becoming increasingly evident. A comprehensive literature search was conducted across multiple databases, including Embase, NCBI, Google Scholar, Elsevier, Science Direct and PubMed, utilising the specific keywords such as 'cervical cancer', 'cervical microbiome', 'vaginal microbiome', 'Human papillomavirus', 'nanoparticles', 'drug delivery' and 'dysbiosis'. Studies published over the past 15 years were reviewed. A total of 400 articles were identified and 65 research articles were finally included. This systematic approach identified relevant studies, enabling an in-depth analysis of microbial species, such as Parabacteroides, Escherichia, Shigella, Gardnerella and Fusobacterium which are recognised as the potential biomarkers for CC diagnosis and progression. Dysbiosis is characterised by a reduction in helpful bacteria and a proliferation of harmful ones. It is linked to chronic inflammation and human papillomavirus infection, both of which facilitate the CC progression. Advanced nanotechnology presents innovative therapeutic options for CC treatment, enhancing drug delivery systems and targeting tumour cells more effectively. Moreover, incorporating nanocarriers into treatment regimens aims to improve the bioavailability and efficacy of existing therapies, potentially transforming the clinical approaches to CC management. This review highlights the dual role of the microbiome as both a diagnostic and prognostic biomarker and elucidates the potential of nanotechnology in optimising treatment strategies, advocating for further research on microbial interactions in cancer pathology.

Unraveling shared and unique genetic causal relationship between gut microbiota and four types of uterine-related diseases: Bidirectional Mendelian inheritance approaches to dissect the "Gut-Uterus Axis"

BACKGROUND

The gut microbiota has emerged as a pivotal factor in the etiology of uterine-related diseases. This study aims to elucidate the genetic causal link between gut microbiota composition and these conditions, focusing on the systemic impact and uterine pathology to better understand the "Gut-Uterus Axis."

METHODS

We utilized pooled data from two different GWAS databases, including data from 209 gut microbiota traits and data from four uterus-related diseases. Bidirectional Mendelian Randomization (MR) approaches, incorporating Bayesian weighting and traditional inverse variance weighting (IVW) methods, were employed to explore causal relationships. The robustness of findings was ensured through sensitivity analyses, outlier testing, and MR-PRESSO analysis.

RESULTS

Seventeen significant associations were identified between gut microbiota traits and uterine-related diseases, suggesting potential causal links. These associations were consistent across sensitivity analyses, affirming the reliability of our results. Conversely, reverse MR analyses did not reveal statistically significant associations between uterine diseases and bacterial traits, indicating a unidirectional influence of gut microbiota on uterine health. These findings highlight the complex interplay within the "Gut-Uterus Axis."

CONCLUSION

This research establishes a causal relationship between gut microbiota and uterine diseases, advocating for targeted interventions to mitigate associated risks. It underscores the interconnectedness of gut and reproductive health, promoting a holistic approach to management and treatment within the "Gut-Uterus Axis".

Effects of vaginal microbiota on human papillomavirus infection and its related diseases

With the knowledge of female reproductive tract microbiota gradually increasing, the connection between vaginal microbiota (VMB) and its related diseases is increasingly highlighted. Manifestation of VMB keeps changing with various dominated bacteria, which can affect the immune response of mucosal barrier and the entrance of pathogens. Human papillomavirus (HPV), as an oncogenic virus, is closely related to viral-associated cancer, such as cervical cancer. According to HPV infection status, VMB can transform into different types, and result in accelerating or restraining the progression of diseases, which have exposed the inner link between VMB and HPV. Therefore, probiotics therapy promises to be a new complementary therapy to rebuild a healthy VMB for patients, but there's still a long way to go before its ready for the clinic. This review focuses on composition, immune response, and application of VMB in HPV and its associated diseases and aims to provide the new ideas and directions for the research on VMB.

Vaginal microbiota and gynecological cancers: a complex and evolving relationship

The vagina hosts a community of microorganisms known as the vaginal microbiota. This community is relatively stable and straightforward, with Lactobacillus species being the most dominant members. The vaginal microbiota has various functions that are essential for maintaining human health and balance. For example, it can metabolise dietary nutrients, produce growth factors, communicate with other bacteria, modulate the immune system, and prevent the invasion of harmful pathogens. When the vaginal microbiota is disrupted, it can lead to diseases and infections. The observed disturbance is distinguished by a reduction in the prevalence of Lactobacillus and a concurrent rise in the number of other bacterial species that exhibit a higher tolerance to low oxygen levels. Gynecologic cancers are a group of cancers that affect the female reproductive organs and tissues, such as the ovaries, uterus, cervix, vagina, vulva, and endometrium. These cancers are a major global health problem for women. Understanding the complex interactions between the host and the vaginal microorganisms may provide new insights into the prevention and treatment of gynecologic cancers. This could improve the quality of life and health outcomes for women.

The Vaginal Microbiota, Human Papillomavirus Infection, and Cervical Carcinogenesis: A Systematic Review in the Latina Population

BACKGROUND

Latina women experience disproportionately higher rates of HPV infection, persistence, and progression to cervical dysplasia and cancer compared to other racial-ethnic groups. This systematic review explores the relationship between the cervicovaginal microbiome and human papillomavirus infection, cervical dysplasia, and cervical cancer in Latinas.

METHODS

The review abides by the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. PubMed, EMBASE, and Scopus databases were searched from January 2000 through November 11, 2022. The review included observational studies reporting on the cervicovaginal microbiota in premenopausal Latina women with human papillomavirus infection, cervical dysplasia, and cervical cancer.

RESULTS

Twenty-five articles were eligible for final inclusion (N = 131,183). Forty-two unique bacteria were reported in the cervicovaginal microbiome of Latinas. Seven bacteria: Lactobacillus crispatus, Lactobacillus iners, Chlamydia trachomatis, Prevotella spp., Prevotella amnii, Fusobacterium spp. and Sneathia spp. were enriched across multiple stages of cervical carcinogenesis in Latinas. Therefore, the total number of reported bacteria includes four bacteria associated with the healthy state, 16 bacteria enriched in human papillomavirus outcomes, 24 unique bacteria associated with abnormal cytology/dysplasia, and five bacteria associated with cervical cancer. Furthermore, three studies reported significantly higher alpha and beta diversity in Latinas with cervical dysplasia and cancer compared to controls. Lactobacillus depletion and an increased abundance of L. iners in Latinas compared to non-Latinas, regardless of human papillomavirus status or lesions, were observed.

CONCLUSIONS

The identification of 42 unique bacteria and their enrichment in cervical carcinogenesis can guide future cervicovaginal microbiome research to better inform cervical cancer prevention strategies in Latinas.

Cervicovaginal microbiota: a promising direction for prevention and treatment in cervical cancer

Cervical cancer is a common malignancy in women, with high incidence rate and mortality. Persistent infection of high-risk human papillomavirus (HPV) is the most important risk factor for cervical cancer and precancerous lesions. Cervicovaginal microbiota (CVM) plays an essential role in the defense of HPV infections and prevention of subsequent lesions. Dominance of Lactobacillus is the key of CVM homeostasis, which can be regulated by host, exogenous and endogenous factors. Dysbiosis of CVM, including altered microbial, metabolic, and immune signatures, can contribute to persist HPV infection, leading to cervical cancer. However, there is no evidence of the causality between CVM and cervical cancer, and the underlying mechanism remains unexplored. Considering the close correlation between CVM dysbiosis and persistent HPV infection, this review will overview CVM, its role in cervical cancer development and related mechanisms, and the prospects for therapeutic applications.