Serologic markers of Chlamydia trachomatis and other sexually transmitted infections and subsequent ovarian cancer risk: Results from the EPIC cohort

The Urogenital System Microbiota: Is It a New Gamechanger in Urogenital Cancers?

The human microbiome, which encompasses microbial communities and their genetic material, significantly influences health and disease, including cancer. The urogenital microbiota, naturally present in the urinary and genital tracts, interact with factors such as age, lifestyle, and health conditions to affect homeostasis and carcinogenesis. Studies suggest that alterations in this microbiota contribute to the development and progression of genitourinary cancers, emphasizing the concept of oncobiome, which refers to microbial genetic contributions to cancer. Similarly, gut microbiota can influence hormone levels and systemic inflammation, impacting cancers such as cervical and prostate cancer. Advanced studies indicate that microbial communities in genitourinary cancers have distinct profiles that may serve as diagnostic biomarkers or therapeutic targets. Dysbiosis of the urinary microbiota correlates with bladder and kidney cancer. Additionally, gut microbiota influence the effectiveness of cancer treatments. However, further research is necessary to clarify causality, the role of microbial metabolites, and hormonal regulation. The aim of this review is to understand that these dynamics present opportunities for innovative cancer diagnostics and therapies, highlighting the need for integration of microbiology, oncology, and genomics to explore the role of microbiota in genitourinary cancers. For this, a comprehensive search of relevant databases was conducted, applying specific inclusion and exclusion criteria to identify studies examining the association between microbiota and urogenital cancers. Research into the mechanisms by which microbiota influence urogenital cancers may pave the way for new diagnostic and therapeutic approaches, ultimately improving patient outcomes.

Appraisal of the causal effect of Chlamydia trachomatis infection on epithelial ovarian cancer risk: a two-sample Mendelian randomisation study

Background

History of Chlamydia trachomatis infection has previously been associated with epithelial ovarian cancer (EOC) in observational studies. We conducted a two-sample univariable Mendelian randomisation (MR) study to examine whether genetically predicted seropositivity to the C. trachomatis major outer membrane protein (momp) D is causally associated with EOC.

Methods

MR analyses employed genetic associations derived from UK Biobank as proxies for momp D seropositivity in 25 509 EOC cases and 40 941 controls that participated in the Ovarian Cancer Association Consortium. Findings were replicated using a GWAS meta-analyses of global biobanks including the UK Biobank, FinnGen and BioBank Japan.

Results

Genetically predicted momp D seropositivity was associated with overall and high-grade serous EOC risk in inverse-variance weighted (IVW) and MR-Egger univariable MR analysis (odds ratio (OR) 1.06; 95% confidence interval (CI) 1.02-1.10, and OR 1.08; 95%CI 1.01-1.16, respectively). Replication yielded similar results for overall EOC (OR 1.11; 95%CI 1.01-1.22).

Conclusion

This MR study supports a causative link between C. trachomatis infection and overall and high-grade serous EOC.

Environment and gynaecologic cancers

In the current era, environmental factors are well established as major causative agents for all cancers especially lung and breast cancer. We sought to review the current available literature on the topic pertaining to gynaecologic cancers. Although a few factors are well established in literature, others need more research to conclude.

Insights into the Two Most Common Cancers of Primitive Gut-Derived Structures and Their Microbial Connections

The gastrointestinal and respiratory systems are closely linked in different ways, including from the embryological, anatomical, cellular, and physiological angles. The highest number (and various types) of microorganisms live in the large intestine/colon, and constitute the normal microbiota in healthy people. Adverse alterations of the microbiota or dysbiosis can lead to chronic inflammation. If this detrimental condition persists, a sequence of pathological events can occur, such as inflammatory bowel disease, dysplasia or premalignant changes, and finally, cancer. One of the most commonly identified bacteria in both inflammatory bowel disease and colon cancer is Escherichia coli. On the other hand, patients with inflammatory bowel disease are at risk of several other diseases-both intestinal (such as malnutrition and intestinal obstruction, besides cancer) and extraintestinal (such as arthritis, bronchiectasis, and cancer risk). Cancers of the lung and colon are the two most common malignancies occurring worldwide (except for female breast cancer). Like the bacterial role in colon cancer, many studies have shown a link between chronic Chlamydia pneumoniae infection and lung cancer. However, in colon cancer, genotoxic colibactin-producing E. coli belonging to the B2 phylogroup may promote tumorigenesis. Furthermore, E. coli is believed to play an important role in the dissemination of cancer cells from the primary colonic site. Currently, seven enteric pathogenic E. coli subtypes have been described. Conversely, three Chlamydiae can cause infections in humans (C. trachomatis may increase the risk of cervical and ovarian cancers). Nonetheless, striking genomic plasticity and genetic modifications allow E. coli to constantly adjust to the surrounding environment. Consequently, E. coli becomes resistant to antibiotics and difficult to manage. To solve this problem, scientists are thinking of utilizing suitable lytic bacteriophages (viruses that infect and kill bacteria). Several bacteriophages of E. coli and Chlamydia species are being evaluated for this purpose.

Seroprevalence of sexually transmitted infections over 44 years - A cross-sectional study in Sweden

BACKGROUND

Sexually transmitted infections (STIs) may cause substantial individual suffering and a large economic burden for society. This study examined the seroprevalence of Chlamydia trachomatis, Mycoplasma genitalium, herpes simplex virus (HSV) types 1 and 2, and several human papillomaviruses (HPV) in the Swedish population over time.

METHODS

The study population consisted of 30-year-old women attending maternity care, and 50 year-old men and women attending health check-ups, from 1975 to 2018. Antibody status was determined by multiplex serology and quantified using median reporter fluorescence intensity (MFI).

RESULTS

A total of 891 samples were analysed (519 from 30-year-old women, 186 from 50 year-old women and 186 from 50 year-old men). Of these, 41.5% showed seropositivity for Chlamydia trachomatis, 16.7% for Mycoplasma genitalium, 70.5% for HSV-1, 14.9% for HSV-2, 13.2% for high-risk HPV, and 8.3% for low-risk HPV. Seropositivity for Mycoplasma genitalium, HSV-1 and especially Chlamydia trachomatis decreased over time.

CONCLUSIONS

There was a decrease over time in Chlamydia trachomatis seroprevalence, probably due to contact tracing, testing and early treatment; this might also have affected Mycoplasma genitalium seroprevalence. Despite the reduction, seroprevalences are still high, so continued and new efforts to reduce STI incidence are essential.

Deciphering the Puzzle: Literature Insights on Chlamydia trachomatis-Mediated Tumorigenesis, Paving the Way for Future Research

Some infectious agents have the potential to cause specific modifications in the cellular microenvironment that could be propitious to the carcinogenesis process. Currently, there are specific viruses and bacteria, such as human papillomavirus (HPV) and Helicobacter pylori, that are well established as risk factors for neoplasia. Chlamydia trachomatis (CT) infections are one of the most common bacterial sexually transmitted infections worldwide, and recent European data confirmed a continuous rise across Europe. The infection is often asymptomatic in both sexes, requiring a screening program for early detection. Notwithstanding, not all countries in Europe have it. Chlamydia trachomatis can cause chronic and persistent infections, resulting in inflammation, and there are plausible biological mechanisms that link the genital infection with tumorigenesis. Herein, we aimed to understand the epidemiological and biological plausibility of CT genital infections causing endometrial, ovarian, and cervical tumors. Also, we covered some of the best suitable in vitro techniques that could be used to study this potential association. In addition, we defend the point of view of a personalized medicine strategy to treat those patients through the discovery of some biomarkers that could allow it. This review supports the need for the development of further fundamental studies in this area, in order to investigate and establish the role of chlamydial genital infections in oncogenesis.

Global epidemiology of epithelial ovarian cancer

Globally, ovarian cancer is the eighth most common cancer in women, accounting for an estimated 3.7% of cases and 4.7% of cancer deaths in 2020. Until the early 2000s, age-standardized incidence was highest in northern Europe and North America, but this trend has changed; incidence is now declining in these regions and increasing in parts of eastern Europe and Asia. Ovarian cancer is a very heterogeneous disease and, even among the most common type, namely epithelial ovarian cancer, five major clinically and genetically distinct histotypes exist. Most high-grade serous ovarian carcinomas are now recognized to originate in the fimbrial ends of the fallopian tube. This knowledge has led to more cancers being coded as fallopian tube in origin, which probably explains some of the apparent declines in ovarian cancer incidence, particularly in high-income countries; however, it also suggests that opportunistic salpingectomy offers an important opportunity for prevention. The five histotypes share several reproductive and hormonal risk factors, although differences also exist. In this Review, we summarize the epidemiology of this complex disease, comparing the different histotypes, and consider the potential for prevention. We also discuss how changes in the prevalence of risk and protective factors might have contributed to the observed changes in incidence and what this might mean for incidence in the future.

Exploring the Relationship between Ovarian Cancer and Genital Microbiota: A Systematic Review and Meta-Analysis

Ovarian cancer (OC) remains a significant health challenge globally, with high mortality rates despite advancements in treatment. Emerging research suggests a potential link between OC development and genital dysbiosis, implicating alterations in the microbiome composition as a contributing factor. To investigate this correlation, a meta-analysis was conducted following PRISMA and MOOSE guidelines, involving eight studies encompassing 3504 patients. Studies investigating the role of upper and inferior genital tract dysbiosis were included, with particular reference to HPV infection and/or history of pelvic inflammatory disease. The analysis revealed no significant difference in genital dysbiosis prevalence between OC patients and healthy controls. Although previous literature suggests associations between dysbiosis and gynecologic cancers, such as cervical and endometrial cancers, the findings regarding OC are inconclusive. Methodological variations and environmental factors may contribute to these discrepancies, underscoring the need for standardized methodologies and larger-scale studies. Despite the limitations, understanding the microbiome's role in OC development holds promise for informing preventive and therapeutic strategies. A holistic approach to patient care, incorporating microbiome monitoring and personalized interventions, may offer insights into mitigating OC risk and improving treatment outcomes. Further research with robust methodologies is warranted to elucidate the complex interplay between dysbiosis and OC, potentially paving the way for novel preventive and therapeutic approaches.

The effect of the female genital tract and gut microbiome on reproductive dysfunction

Microorganisms are ubiquitous in the human body; they are present in various areas including the gut, mouth, skin, respiratory tract, and reproductive tract. The interaction between the microbiome and reproductive health has become an increasingly compelling area of study. Disruption of the female genital tract microbiome can significantly impact the metabolism of amino acids, carbohydrates, and lipids, increasing susceptibility to reproductive tract diseases such as vaginitis, chronic endometritis, endometrial polyps, endometriosis, and polycystic ovary syndrome. The gut microbiome, considered an endocrine organ, plays a crucial role in the reproductive endocrine system by interacting with hormones like estrogen and androgens. Imbalances in the gut microbiome composition can lead to various diseases and conditions, including polycystic ovary syndrome, endometriosis, and cancer, although research on their mechanisms remains limited. This review highlights the latest advancements in understanding the female genital tract and gut microbiomes in gynecological diseases. It also explores the potential of microbial communities in the treatment of reproductive diseases. Future research should focus on identifying the molecular mechanisms underlying the association between the microbiome and reproductive diseases to develop new and effective strategies for disease prevention, diagnosis, and treatment related to female reproductive organs.

Insights into the Microbial Composition of Intratumoral, Reproductive Tract, and Gut Microbiota in Ovarian Cancer Patients

According to the latest global cancer data, ovarian cancer is the deadliest among all gynecological malignant tumors and ranks fifth in terms of mortality. Its etiology and pathogenesis are unknown, and the 5-year survival rate of patients with advanced ovarian cancer is only 40% (Sung et al. CA Cancer J Clin 71:209-49, 2021). Recent research has shown that the human microbiota plays a crucial role in the development and progression of tumors, including ovarian cancer. Numerous studies have highlighted the complex connections between the reproductive tract microbiota, intestinal microbiota, and ovarian cancer (Jacobson et al. PeerJ 9:e11574, 2021). Therefore, this chapter will delve into composition, function, and the correlation between microbiota and immunity in the field of ovarian cancer microbiota, as well as the potential of bacteria in therapeutics and diagnostics of ovarian cancer.

Pelvic inflammatory disease and risk of epithelial ovarian cancer: a national population-based case-control study in Sweden

BACKGROUND

Epithelial ovarian cancer is an insidious disease, and women are often diagnosed when the disease is beyond curative treatment. Accordingly, identifying modifiable risk factors is of paramount importance. Inflammation predisposes an individual to cancer in various organs, but whether pelvic inflammatory disease is associated with an increased risk of epithelial ovarian cancer has not been fully determined.

OBJECTIVE

This study aimed to investigate a possible association between clinically verified pelvic inflammatory disease and the risk of epithelial ovarian cancer.

STUDY DESIGN

In this national population-based case-control study, all women in Sweden diagnosed with epithelial ovarian cancer between 1999 and 2020 and 10 controls for each were identified, matched for age and residential district. Using several Swedish nationwide registers, data on previous pelvic inflammatory disease and potential confounding factors (age, parity, educational level, and previous gynecologic surgery) were retrieved. Adjusted odds ratios and 95% confidence intervals were estimated using conditional logistic regression. Histotype-specific analyses were performed for the subgroup of women diagnosed with epithelial ovarian cancer between 2015 and 2020. Moreover, hormonal contraceptives and menopausal hormone therapy were adjusted in addition to the aforementioned confounders.

RESULTS

This study included 15,072 women with epithelial ovarian cancer and 141,322 controls. Most women (9102 [60.4%]) had serous carcinoma. In a subgroup of cases diagnosed between 2015 and 2020, high-grade serous carcinoma (2319 [60.0%]) was identified. A total of 168 cases (1.1%) and 1270 controls (0.9%) were diagnosed with pelvic inflammatory disease. Previous pelvic inflammatory disease was associated with an increased risk of epithelial ovarian cancer (adjusted odds ratio, 1.39; 95% confidence interval, 1.17-1.66) and serous carcinoma (adjusted odds ratio, 1.46; 95% confidence interval, 1.18-1.80) for the entire study population. For the subgroup of women diagnosed in 2015-2020, pelvic inflammatory disease was associated with high-grade serous carcinoma (adjusted odds ratio, 1.43; 95% confidence interval, 1.01-2.04). The odds ratios of the other histotypes were as follows: endometrioid (adjusted odds ratio, 0.13; 95% confidence interval, 0.02-1.06), mucinous (adjusted odds ratio, 1.55; 95% confidence interval, 0.56-4.29), and clear cell carcinoma (adjusted odds ratio, 2.30; 95% confidence interval, 0.90-5.86). A dose-response relationship was observed between the number of pelvic inflammatory disease episodes and the risk of epithelial ovarian cancer (Ptrend<.001).

CONCLUSION

A history of pelvic inflammatory disease is associated with an increased risk of epithelial ovarian cancer and a dose-response relationship is evident. Histotype-specific analyses show an association with increased risk of serous epithelial ovarian cancer and high-grade serous carcinoma and potentially also with clear cell carcinoma, but there is no significant association with other histotypes. Infection and inflammation of the upper reproductive tract might have serious long-term consequences, including epithelial ovarian cancer.

Sexually Transmitted Infections and Risk of Epithelial Ovarian Cancer: Results From the Finnish Maternity Cohort

BACKGROUND

Sexually transmitted infections, specifically Chlamydia trachomatis (CT), may be associated with epithelial ovarian cancer (EOC) risk. The association between CT and EOC subtypes is unclear. Our aim was to investigate whether history of CT and other infections (Mycoplasma genitalium [MG], herpes simplex virus type 2 [HSV-2], and human papillomavirus [HPV]) are associated with EOC risk by histotype.

METHODS

We measured antibodies (Abs) to CT, MG, HSV-2, and HPV-16/18 in serum samples in a nested case-control study in the Finnish Maternity Cohort (N = 484 cases 1:1 matched to controls). Logistic regression was used to calculate relative risks (RRs) and 95% confidence intervals (CIs) in seropositive versus seronegative individuals in all cases, as well as serous (n = 249), clear cell and endometrioid (n = 91), and mucinous (n = 144) EOC.

RESULTS

CT seropositivity was not associated with EOC risk (eg, CT pGP3-Ab: RR, 0.92 [95% CI, .72-1.19]), regardless of disease subtype. We observed a positive association between MG seropositivity and mucinous EOC (RR, 1.66 [95% CI, 1.09-2.54]; P for heterogeneity by histotype ≤ .001), but not other subtypes. No associations were observed with seropositivity to multiple STIs.

CONCLUSIONS

CT infection was not associated with EOC risk, with associations observed only for MG and mucinous EOC. Mechanisms linking MG to mucinous EOC remain to be elucidated.

The microbiome and ovarian cancer: insights, implications, and therapeutic opportunities

Ovarian cancer is the leading cause of gynecologic cancer death in the United States. Most ovarian cancer patients are diagnosed with advanced-stage disease, which poses a challenge for early detection and effective treatment. At present, cytoreductive surgery and platinum-based chemotherapy are foundational for patients with newly diagnosed ovarian cancer, but unfortunately, most patients will recur and die of their disease. Therefore, there is a significant need to seek innovative, novel approaches for early detection and to overcome chemoresistance for ovarian cancer patients. The microbiome, comprising diverse microbial communities inhabiting various body sites, is vital in maintaining human health. Changes to the diversity and composition of the microbial communities impact the microbiota-host relationship and are linked to diseases, including cancer. The microbiome contributes to carcinogenesis through various mechanisms, including altered host immune response, modulation of DNA repair, upregulation of pro-inflammatory pathways, altered gene expression, and dysregulated estrogen metabolism. Translational and clinical studies have demonstrated that specific microbes contribute to ovarian cancer development and impact chemotherapy’s efficacy. The microbiome is malleable and can be altered through different approaches, including diet, exercise, medications, and fecal microbiota transplantation. This review provides an overview of the current literature regarding ovarian cancer and the microbiome of female reproductive and gastrointestinal tracts, focusing on mechanisms of carcinogenesis and options for modulating the microbiota for cancer prevention and treatment. Advancing our understanding of the complex relationship between the microbiome and ovarian cancer may provide a novel approach for prevention and therapeutic modulation in the future.

A single-cell landscape of pre- and post-menopausal high-grade serous ovarian cancer ascites

High-grade serous ovarian cancer (HGSOC) is a hormone-related cancer with high mortality and poor prognosis. Based on the transcriptome of 57,444 cells in ascites from 10 patients with HGSOC (including 5 pre-menopausal and 5 post-menopausal patients), we identified 14 cell clusters which were further classified into 6 cell types, including T cells, B cells, NK cells, myeloid cells, epithelial cells, and stromal cells. We discovered an increased proportion of epithelial cells and a decreased proportion of T cells in pre-menopausal ascites compared with post-menopausal ascites. GO analysis revealed the pre-menopausal tumor microenvironments (TME) are closely associated with viral infection, while the post-menopausal TME are mostly related to the IL-17 immune pathway. SPP1/CD44-mediated crosstalk between myeloid cells and B cells, NK cells, and stromal cells mainly present in the pre-menopausal group, while SPP1/PTGER4 -mediated crosstalk between myeloid cells and epithelial cells mostly present in the post-menopausal group.

The Association of Kidney Function and Inflammatory Biomarkers with Epithelial Ovarian Cancer Risk

BACKGROUND

One of the mechanisms of ovarian tumorigenesis is through inflammation. Kidney dysfunction is associated with increased inflammation; thus, we assessed its relationship with ovarian cancer risk.

METHODS

In prospectively collected samples, we evaluated the association of kidney function markers and C-reactive protein (CRP) with ovarian cancer risk in the UK Biobank. We used multivariable-adjusted Cox proportional hazards models to evaluate quartiles of serum and urine markers with ovarian cancer risk overall and by histology. We assessed effect modification by CRP (≤3.0, >3.0 mg/L).

RESULTS

Among 232,908 women (1,110 ovarian cancer cases diagnosed from 2006-2020), we observed no association between estimated glomerular filtration rate and ovarian cancer risk (Q4 vs. Q1: HR, 1.00; 95% confidence intervals, 0.83-1.22). Potassium was associated with endometrioid (Q4 vs. Q1: 0.33, 0.11-0.98) and clear cell (4.74, 1.39-16.16) tumors. Poor kidney function was associated with a nonsignificant increase in ovarian cancer risk among women with CRP>3.0 mg/L (e.g., uric acid Q4 vs. Q1; 1.23, 0.81-1.86), but not CRP≤3.0 mg/L (0.83, 0.66-1.05). Other associations did not vary across CRP categories.

CONCLUSIONS

Kidney function was not clearly associated with ovarian cancer risk. Larger studies are needed to evaluate possible histology specific associations. Given the suggestive trend for increased ovarian cancer risk in women with poor kidney function and high CRP, future work is needed, particularly in populations with a high prevalence of inflammatory conditions.

IMPACT

This study provided the first evaluation of markers of kidney function in relation to ovarian cancer risk.

Prevention of Epithelial Ovarian Cancer

Given the challenges with achieving effective and durable treatment for epithelial ovarian cancer, primary prevention is highly desirable. Fortunately, decades of research have provided evidence for several strategies that can be deployed to optimize risk reduction. These include surgery, chemoprevention, and lifestyle factor modifications. These broad categories vary in terms of the magnitude of risk reduction possible, the possible short-term and long-term side effects, the degree of difficulty, and acceptability. Thus, the concept of a risk-based model to personalize preventive interventions is advocated to guide discussion between care providers and women at risk. For women with inherited major gene mutations that greatly increase risk of ovarian cancer, surgical approaches have favorable risk to benefit ratios. Chemoprevention and lifestyle factor modifications portend a lower degree of risk reduction but confer lower risk of undesirable side effects. Since complete prevention is not currently possible, better methods for early detection remain a high priority.

Crosstalk between the Resident Microbiota and the Immune Cells Regulates Female Genital Tract Health

The female genital tract (FGT) performs several functions related to reproduction, but due to its direct exposure to the external environment, it may suffer microbial infections. Both the upper (uterus and cervix) and lower (vagina) FGT are covered by an epithelium, and contain immune cells (macrophages, dendritic cells, T and B lymphocytes) that afford a robust protection to the host. Its upper and the lower part differ in terms of Lactobacillus spp., which are dominant in the vagina. An alteration of the physiological equilibrium between the local microbiota and immune cells leads to a condition of dysbiosis which, in turn, may account for the outcome of FGT infection. Aerobic vaginitis, bacterial vaginosis, and Chlamydia trachomatis are the most frequent infections, and can lead to severe complications in reproduction and pregnancy. The use of natural products, such as probiotics, polyphenols, and lactoferrin in the course of FGT infections is an issue of current investigation. In spite of positive results, more research is needed to define the most appropriate administration, according to the type of patient.

An Overview of Selected Bacterial Infections in Cancer, Their Virulence Factors, and Some Aspects of Infection Management

In cancer development and its clinical course, bacteria can be involved in etiology and secondary infection. Regarding etiology, various epidemiological studies have revealed that Helicobacter pylori can directly impact gastric carcinogenesis. The Helicobacter pylori-associated virulence factor cytotoxin-associated gene A perhaps plays an important role through different mechanisms such as aberrant DNA methylation, activation of nuclear factor kappa B, and modulation of the Wnt/β-catenin signaling pathway. Many other bacteria, including Salmonella and Pseudomonas, can also affect Wnt/β-catenin signaling. Although Helicobacter pylori is involved in both gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma, its role in the latter disease is more complicated. Among other bacterial species, Chlamydia is linked with a diverse range of diseases including cancers of different sites. The cellular organizations of Chlamydia are highly complex. Interestingly, Escherichia coli is believed to be associated with colon cancer development. Microorganisms such as Escherichia coli and Pseudomonas aeruginosa are frequently isolated from secondary infections in cancer patients. In these patients, the common sites of infection are the respiratory, gastrointestinal, and urinary tracts. There is an alarming rise in infections with multidrug-resistant bacteria and the scarcity of suitable antimicrobial agents adversely influences prognosis. Therefore, effective implementation of antimicrobial stewardship strategies is important in cancer patients.

Update in Epidemiology and Management of Mycoplasma genitalium Infections

Mycoplasma genitalium is a frequent cause of urogenital syndromes in men and women and is associated with adverse sequelae in women. M genitalium also infects the rectum, and may cause proctitis, but rarely infects the pharynx. Diagnosis requires nucleic acid amplification testing. Antibiotic resistance is widespread: more than half of infections are resistant to macrolides and fluoroquinolone resistance is increasing. Resistance-guided therapy is recommended for symptomatic patients, involving initial treatment with doxycycline to reduce organism load followed by azithromycin for macrolide-sensitive infections or moxifloxacin for macrolide-resistant infections. Neither screening nor tests of cure are recommended in asymptomatic persons.

Mycoplasma genitalium infection in the female reproductive system: Diseases and treatment

Mycoplasma genitalium is a newly emerged sexually transmitted disease pathogen and an independent risk factor for female cervicitis and pelvic inflammatory disease. The clinical symptoms caused by M. genitalium infection are mild and easily ignored. If left untreated, M. genitalium can grow along the reproductive tract and cause salpingitis, leading to infertility and ectopic pregnancy. Additionally, M. genitalium infection in late pregnancy can increase the incidence of preterm birth. M. genitalium infections are often accompanied by co-infection with other sexually transmitted pathogens (Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis) and viral infections (Human Papilloma Virus and Human Immunodeficiency Virus). A recent study suggested that M. genitalium plays a role in tumor development in the female reproductive system. However, few studies endorsed this finding. In recent years, M. genitalium has evolved into a new "superbug" due to the emergence of macrolide-and fluoroquinolone-resistant strains leading to frequent therapy failures. This review summarizes the pathogenic characteristics of M. genitalium and the female reproductive diseases caused by M. genitalium (cervicitis, pelvic inflammatory disease, ectopic pregnancy, infertility, premature birth, co-infection, reproductive tumors, etc.), as well as its potential relationship with reproductive tumors and clinical treatment.

Association of Chlamydia and Mycoplasma infections with susceptibility to ovarian cancer: A systematic review and meta-analysis

BACKGROUND

Ovarian cancer is one of the most prevalent cancers with a high mortality rate in women. Published studies indicate that inflammation, DNA damage, and pelvic inflammatory disease (PID) are the most important risk factors for ovarian cancer and this could be induced and exacerbated by infectious agents such as Chlamydia trachomatis and Mycoplasma genitalium. The aim of this study was to determine the association between Chlamydia and Mycoplasma infections and the risk of ovarian cancer.

METHODS

We carried out a comprehensive search of PubMed, Scopus, Web of Science, Embase, and Google Scholar without limitation on publication date. All relevant studies which investigatived probable potential connection between Chlamydia and Mycoplasma infection and development of ovarian cancer were included.

RESULTS

Eighteen studies comprising a total of 8207 patients were evaluated in the study and this showed that the frequency of infection with Chlamydia and Mycoplasma among ovarian cancer patients was 32.6 % and 23 %, respectively. The results suggested that Chlamydia trachomatis infection increased the overall risk for ovarian cancer by 1.344 fold (OR: 1.344; 95 %CI: 1.19-1.50). Moreover, infection with Mycoplasma infections showed a week but not significant increased risk of ovarian cancer (OR: 1.12; 95 %CI: 0.86-1.44). However, the test for heterogeneity was significant among these studies.

CONCLUSION

This study confirmed the clinical relevance of Chlamydia and Mycoplasma infection and development of the ovarian cancer risk, although the significance was marginal and study heterogeneity was significant. This highlights the need for further studies in this area.

Etiopathogenesis of ovarian cancer. An inflamm-aging entity?

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Ovarian cancer (OvCa) is a multifactorial disease.

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Several factors are involved in age-related increases in carcinogenesis.

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Exposure to inflammatory mediators contributes to increased cell division and genetic and epigenetic changes.

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We discuss the current carcinogenic hypotheses, sites of origin, and etiological factors of OvCa.

Ovarian cancer is one of the most common gynecologic cancers and has the highest mortality rate. The risk/protective factors of ovarian cancer suggest that its etiology is multifactorial. Several factors are involved in age-related increases in carcinogenesis, including the accumulation of senescent cells, inflammaging (a chronic inflammatory state that persists in the elderly), and immunosenescence (aging of the immune system) changes associated with poor immune surveillance. At sites of inflammation, exposure to high levels of inflammatory mediators, such as reactive oxygen species, cytokines, prostaglandins, and growth factors, contributes to increased cell division and genetic and epigenetic changes. These exposure-induced changes promote excessive cell proliferation, increased survival, malignant transformation, and cancer development. Furthermore, the proinflammatory tumor microenvironment contributes to ovarian cancer metastasis and chemoresistance.

This narrative review of the literature was carried out to delineate the possible role of inflammaging in the etiopathogenesis of ovarian cancer development. We discuss the current carcinogenic hypotheses, sites of origin, and etiological factors of ovarian cancer. Treatment of inflammation may represent an attractive strategy for both the prevention and therapy of ovarian cancer.

Antibodies as biomarkers for cancer risk: a systematic review

Increasing evidence has linked the humoral immune response with the development of various cancers. Therefore, there is growing interest in investigating the predictive value of antibodies to assess overall and tissue site-specific cancer risk. Given the large amount of antibody types and the broad scope of the search (i.e. cancer risk), the primary aim of this systematic review was to present an overview of the most researched antibodies (i.e. immunoglobulin (Ig) isotypes (IgG, IgM, IgA, and IgE), tumour and self-antigen-reactive antibodies, infection-related antibodies) in relation to overall and site-specific cancer risk. We identified various antibody types that have been associated with the risk of cancer. While no significant associations were found for IgM serum levels, studies found an inconsistent association among IgE, IgA, and IgG serum levels in relation to cancer risk. When evaluating antibodies against infectious agents, most studies reported a positive link with specific cancers known to be associated with the specific agent recognized by serum antibodies (i.e. helicobacter pylori and gastric cancer, hepatitis B virus and hepatocellular carcinoma, and human papillomavirus and cervical cancer). Several reports identified autoantibodies, as single biomarkers (e.g. anti-p53, anti-MUC1, and anti-CA125) but especially in panels of multiple autoantibodies, to have potential as diagnostic biomarkers for specific cancer types. Overall, there is emerging evidence associating certain antibodies to cancer risk, especially immunoglobulin isotypes, tumour-associated antigen-specific, and self-reactive antibodies. Further experimental studies are necessary to assess the efficacy of specific antibodies as markers for the early diagnosis of cancer.

Cancer Microbiology

Microbes play important roles in cancer from direct carcinogenic effects to their use in treatment. Cancers caused by microorganisms account for approximately 15% of cancers, primarily in low- and middle-income countries. Unique features of infectious carcinogens include their transmissibility, mutability, and specific immune interactions, which provide challenges and opportunities for cancer prevention and treatment. For these agents, infection control through exposure reduction, antivirals, antibiotics, and vaccines is cancer control. In addition, developing evidence suggests that microorganisms including the human microbiome can indirectly modulate cancer formation and influence the effectiveness and toxicity of cancer treatments. Finally, microorganisms themselves can be used to prevent or treat cancer. The convergence of these factors signals the emergence of a new field, cancer microbiology. Recognition of cancer microbiology will spur research, stimulate cross-disciplinary training, inform drug development, and improve public health.

A More Diverse Cervical Microbiome Associates with Better Clinical Outcomes in Patients with Endometriosis: A Pilot Study

Infection-induced chronic inflammation is common in patients with endometriosis. Although microbial communities in the reproductive tracts of patients have been reported, little was known about their dynamic profiles during disease progression and complication development. Microbial communities in cervical mucus were collected by cervical swabs from 10 healthy women and 23 patients, and analyzed by 16S rRNA amplicon sequencing. The abundance, ecological relationships and functional networks of microbiota were characterized according to their prevalence, clinical stages, and clinical features including deeply infiltrating endometriosis (DIE), CA125, pain score and infertility. Cervical microbiome can be altered during endometriosis development and progression with a tendency of increased Firmicutes and decreased Actinobacteria and Bacteroidetes. Distinct from vaginal microbiome, upregulation of Lactobacillus, in combination with increased Streptococcus and decreased Dialister, was frequently associated with advanced endometriosis stages, DIE, higher CA125 levels, severe pain, and infertility. Significantly, reduced richness and diversity of cervical microbiome were detected in patients with more severe clinical symptoms. Clinical treatments against infertility can partially reverse the ecological balance of microbes through remodeling nutrition metabolism and transport and cell-cell/cell-matrix interaction. This study provides a new understanding on endometriosis development and a more diverse cervical microbiome may be beneficial for patients to have better clinical outcomes.

Precision strategies for cancer treatment by modifying the tumor-related bacteria

Research on the roles of the bacteria in tumor development and progression is a rapidly emerging field. Increasing evidence links bacteria with the modification of the tumor immune microenvironment, which greatly influences the antitumor response. In view of the individual immune effects of various bacteria in various tumors, developing personalized bacteria-modulating therapy may be a key to successful antitumor treatment. This review emphasizes the critical role of the bacteria in immune regulation, including both the tumor bacteria and gut bacteria. Aiming at tumor-related bacteria, we focus on various precise modulation strategies and discuss their impact and potential for tumor suppression. Finally, engineered bacteria with tumor-targeting ability could achieve precise delivery of various payloads into tumors, acting as a precision tool. Therefore, a precise tumor-related bacteria therapy may be a promising approach to suppress the development of tumors, as well as an adjuvant therapy to improve the antitumor efficacy of other approaches. KEY POINTS: • The mini-review updates the knowledge on complex effect of bacteria in TME. • Insight into the interaction and adjustment of bacteria in gut for TME. • Prospects and limitations of bacteria-related personalized therapy in the clinical anticancer therapy.

Is There a Hidden Burden of Disease as a Result of Epigenetic Epithelial-to-Mesenchymal Transition Following Chlamydia trachomatis Genital Tract Infection?

Chlamydia trachomatis (CT), the most common bacterial sexually transmitted infection worldwide, has been widely researched for its involvement in many disease pathologies in the reproductive tract, including pelvic inflammatory disease, ectopic pregnancy, and tubal factor infertility. Recent findings, through the efforts to understand the pathogenesis of CT, suggest that CT can induce the process of epithelial-to-mesenchymal transition (EMT) through epigenetic changes in the epithelium of the female reproductive tract. This literature review aims to analyze the evidence for CT's ability to promote EMT and to pinpoint the areas that merit further investigation.

Chlamydia trachomatis, Pelvic Inflammatory Disease, and Epithelial Ovarian Cancer

Epidemiologic, clinical, molecular and translational research findings support an interrelationship between Chlamydia trachomatis, pelvic inflammatory disease (PID), and epithelial ovarian cancer (EOC). Overall, the link between C. trachomatis, PID, and EOC seems to be relatively weak, although nondifferential misclassification bias may have attenuated the results. The predominant tubal origin of EOC and the role of chronic inflammation in tumorigenesis suggest that the association is biologically plausible. Thus, C. trachomatis and PID may represent potential risk factors or risk markers for EOC. However, many steps in this chain of events are still poorly understood and need to be addressed in future studies. Research gaps include time of exposure in relation to the long-term consequences and lag time to EOC. Data of differential risk for EOC between chlamydial and nonchlamydial PID is also needed. Another major research gap has been the absence of high-performance biomarkers for C. trachomatis, PID, and EOC, as well as EOC precursors. Biomarkers for C. trachomatis and PID leading to increased risk of EOC should be developed. If the association is confirmed, C. trachomatis and PID prevention efforts may play a role in reducing the burden of EOC.

The Microbiome and Gynecologic Cancer: Current Evidence and Future Opportunities

PURPOSE OF REVIEW

We review the emerging evidence regarding the relationship between the microbiota of the gastrointestinal and female reproductive tracts and gynecologic cancer.

RECENT FINDINGS

The microbiome has essential roles in maintaining health. In recent years, the microbiota of the gastrointestinal and female reproductive tracts have been linked to many diseases, including gynecologic cancer. Alterations to the bacterial populations in a microbiota, or dysbiosis, have been shown to favor a pro-carcinogenic state through altered immune responses, dysregulated hormone metabolism, and modulation of the cell cycle. Pre-clinical and clinical studies have emerged, demonstrating that specific bacteria or microbial communities may be associated with increased risk for uterine, ovarian, and cervical cancers. Notably, numerous studies have linked a non-Lactobacillus-dominant vaginal microbiota, composed of anaerobic bacteria, with HPV infection, persistence, and development of invasive cervical cancer. Similarly, next-generation high-throughput sequencing techniques have enabled the characterization of unique microbiotas in patients with malignant and benign gynecologic conditions, shedding light on new associations between bacterial species and gynecologic cancers. Harnessing the power of the microbiome for early diagnosis, therapeutic intervention and modulation creates tremendous potential to optimize gynecologic cancer outcomes in the future.

Mechanisms of High-Grade Serous Carcinogenesis in the Fallopian Tube and Ovary: Current Hypotheses, Etiologic Factors, and Molecular Alterations

Ovarian high-grade serous carcinomas (HGSCs) are a heterogeneous group of diseases. They include fallopian-tube-epithelium (FTE)-derived and ovarian-surface-epithelium (OSE)-derived tumors. The risk/protective factors suggest that the etiology of HGSCs is multifactorial. Inflammation caused by ovulation and retrograde bleeding may play a major role. HGSCs are among the most genetically altered cancers, and TP53 mutations are ubiquitous. Key driving events other than TP53 mutations include homologous recombination (HR) deficiency, such as BRCA 1/2 dysfunction, and activation of the CCNE1 pathway. HR deficiency and the CCNE1 amplification appear to be mutually exclusive. Intratumor heterogeneity resulting from genomic instability can be observed at the early stage of tumorigenesis. In this review, I discuss current carcinogenic hypotheses, sites of origin, etiologic factors, and molecular alterations of HGSCs.

The Interaction Between Microorganisms, Metabolites, and Immune System in the Female Genital Tract Microenvironment

The female reproductive tract microenvironment includes microorganisms, metabolites, and immune components, and the balance of the interactions among them plays an important role in maintaining female reproductive tract homeostasis and health. When any one of the reproductive tract microorganisms, metabolites, or immunity is out of balance, it will affect the other two, leading to the occurrence and development of diseases and the appearance of corresponding symptoms and signs, such as infertility, miscarriage, premature delivery, and gynecological tumors caused by infectious diseases of the reproductive tract. Nutrients in the female reproductive tract provide symbiotic and pathogenic microorganisms with a source of nutrients for their own reproduction and utilization. At the same time, this interaction with the host forms a variety of metabolites. Changes in metabolites in the host reproductive tract are related not only to the interaction between the host and microbiota under dysbiosis but also to changes in host immunity or the environment, all of which will participate in the pathogenesis of diseases and lead to disease-related phenotypes. Microorganisms and their metabolites can also interact with host immunity, activate host immunity, and change the host immune status and are closely related to persistent genital pathogen infections, aggravation of infectious diseases, severe pregnancy outcomes, and even gynecological cancers. Therefore, studying the interaction between microorganisms, metabolites, and immunity in the reproductive tract cannot only reveal the pathogenic mechanisms that lead to inflammation of the reproductive tract, adverse pregnancy outcomes and tumorigenesis but also provide a basis for further research on the diagnosis and treatment of targets.

The Microbiome and Cancer: Creating Friendly Neighborhoods and Removing the Foes Within

The human body is colonized by the microbial cells that are estimated to be as abundant as human cells, yet their genome is roughly 100 times the human genome, providing significantly more genetic diversity. The past decade has observed an explosion of interest in examining the existence of microbiota in the human body and understanding its role in various diseases including inflammatory bowel disease, neurologic diseases, cardiovascular disorders, and cancer. Many studies have demonstrated differential community composition between normal tissue and cancerous tissue, paving the way for investigations focused on deciphering the cause-and-effect relationships between specific microbes and initiation and progression of various cancers. Also, evolving are the strategies to alter tumor-associated dysbiosis and move it toward eubiosis with holistic approaches to change the entire neighborhood or to neutralize pathogenic strains. In this review, we discuss important pathogenic bacteria and the underlying mechanisms by which they affect cancer progression. We summarize key microbiota alterations observed in multiple tumor niches, their association with clinical stages, and their potential use in cancer diagnosis and management. Finally, we discuss microbiota-based therapeutic approaches.