Infections and cancer: the "fifty shades of immunity" hypothesis

Special Issue "Bacterial Toxins and Cancer"

Infection is a major contributor to the development of cancer, with more than 15% of new cancer diagnoses estimated to be caused by infection [...].

Intratumoral Microbiota Changes with Tumor Stage and Influences the Immune Signature of Oral Squamous Cell Carcinoma

Characterization of the oral microbiota profile through various studies has shown an association between the microbiome and oral cancer; however, stage-specific determinants of dynamic changes in microbial communities of oral cancer remain elusive. Additionally, the influence of the intratumoral microbiota on the intratumoral immune system remains largely unexplored. Therefore, this study aims to stratify microbial abundance in the early-onset and subsequent stages of oral cancer and analyze their influence on clinical-pathological and immunological features. The microbiome composition of tissue biopsy samples was identified using 16S rRNA amplicon sequencing, while intratumoral and systemic immune profiling was done with flow cytometry and immunohistochemistry-based analysis. The bacterial composition differed significantly among precancer, early cancer, and late cancer stages with the enrichment of genera Capnocytophaga, Fusobacterium, and Treponema in the cancer group, while Streptococcus and Rothia were enriched in the precancer group. Late cancer stages were significantly associated with Capnocytophaga with high predicting accuracy, while Fusobacterium was associated with early stages of cancer. A dense intermicrobial and microbiome-immune network was observed in the precancer group. At the cellular level, intratumoral immune cell infiltration of B cells and T cells (CD4+ and CD8+) was observed with enrichment of the effector memory phenotype. Naive and effector subsets of tumor-infiltrating lymphocytes (TILs) and related gene expression were found to be distinctly associated with bacterial communities; most importantly, highly abundant bacterial genera of the tumor microenvironment were either negatively correlated or not associated with the effector lymphocytes, which led to the conclusion that the tumor microenvironment favors an immunosuppressive and nonimmunogenic microbiota. IMPORTANCE The gut microbiome has been explored extensively for its importance in the modulation of systemic inflammation and immune response; in contrast, the intratumoral microbiome is less studied for its influence on immunity in cancer. Given the established correlation between intratumoral lymphocyte infiltration and patient survival in cases of solid tumors, it was pertinent to explore the extrinsic factor influencing immune cell infiltration in the tumor. Modulation of intratumoral microbiota could have a beneficial effect on the antitumor immune response. This study stratifies the microbial profile of oral squamous cell carcinoma starting from precancer to late-stage cancer and provides evidence for their immunomodulatory role in the tumor microenvironment. Our results suggest combining microbiome study with immunological signatures of tumors for their prognostic and diagnostic application.

IL17RB and IL17REL Expression Are Associated with Improved Prognosis in HPV-Infected Head and Neck Squamous Cell Carcinomas

Changes in the cellular secretome are implicated in virus infection, malignancy, and anti-tumor immunity. We analyzed the association between transcriptional signatures (TS) from 24 different immune and stromal cell types on the prognosis of HPV-infected and HPV-free head and neck squamous carcinoma (HNSCC) patients from The Cancer Genome Atlas (TCGA) cohort. We found that HPV-positive HNSCC patients have tumors with elevated immune cell TS and improved prognosis, which was specifically associated with an increased tumor abundance of memory B and activated natural killer (NK) cell TS, compared to HPV-free HNSCC patients. HPV-infected patients upregulated many transcripts encoding secreted factors, such as growth factors, hormones, chemokines and cytokines, and their cognate receptors. Analysis of secretome transcripts and cognate receptors revealed that tumor expression of IL17RB and IL17REL are associated with a higher viral load and memory B and activated NK cell TS, as well as improved prognosis in HPV-infected HNSCC patients. The transcriptional parameters that we describe may be optimized to improve prognosis and risk stratification in the clinic and provide insights into gene and cellular targets that may potentially enhance anti-tumor immunity mediated by NK cells and memory B cells in HPV-infected HNSCC patients.

Clostridium difficile Infection Is Associated With Decreased Prostate Cancer Risk: A Retrospective Cohort Study

Background Clostridium difficile (C. difficile) is one of the most common hospital-acquired infections and causes the release of various cytokines. Prostate cancer (PC) is the second most common cancer in men worldwide. As infections have been associated with decreased cancer risk, the effects of C. difficile on the risk of developing PC were analyzed. Methodology Using the PearlDiver national database, a retrospective cohort analysis was performed to evaluate the relationship between a prior history of C. difficile infection and subsequent development of PC. International Classification of Disease Ninth and Tenth Revision codes were used to evaluate the incidence of PC between January 2010 and December 2019 in patients with and without a history of C. difficile infection. The groups were matched by age range, Charlson Comorbidity Index (CCI), and antibiotic treatment exposure. Standard statistical methods, including relative risk and odds ratio (OR) analyses, were utilized to test for significance. Demographic information was subsequently analyzed and compared between experimental and control groups. Results A total of 79,226 patients were identified in both the infected and control groups matched by age and CCI. The incidence of PC was 1,827 (2.56%) in the C. difficile group and 5,565 (7.79%) in the control group (p < 2.2 × 10^-16; OR = 0.390, 95% confidence interval (CI) = 0.372-0.409). Subsequent matching by antibiotic treatment resulted in two groups of 16,772 patients. PC incidence was 272 (1.62%) in the C. difficile group and 663 (3.95%) in the control group (p < 2.2 × 10^-16; OR = 0.467, 95% CI = 0.431-0.507). Conclusions Results from this retrospective cohort study demonstrate that C. difficile infection is associated with a reduced incidence of PC. Future studies are recommended to investigate the potential effect of the immune system and cytokines related to C. difficile infection on PC.

Nontyphoidal Salmonella Infection Associated with Subsequent Risk of Hematological Malignancies: A Nationwide Population-Based Cohort Study

This study aimed to investigate the relationship between nontyphoidal salmonellosis (NTS) and new-onset hematological malignancy. We conducted a 17-year nationwide, population-based, retrospective cohort study to examine the association between NTS and the risk of hematological malignancies by using the Longitudinal Health Insurance Database (LHID) of Taiwan. Participants were enrolled from 2000 to 2015 and were monitored until 2017. We traced the years 1998-2000 to ensure that the cases included were newly diagnosed with NTS. The NTS cohort included 13,790 patients with newly diagnosed NTS between 2000 and 2015. Each patient was propensity score matched at a 1:4 ratio with people without NTS. Cumulative incidence, hazard ratios (HRs), and 95% confidence intervals (CIs) were calculated after adjusting for age, sex, income, urbanization, and medical comorbidities. The adjusted hazard ratio (aHR) of hematological malignancies for NTS patients relative to those without NTS was 1.42 (95% CI 0.91-2.20). In the age subgroup analysis, NTS had a significantly greater risk of hematological malignancies for patients older than 60 (aHR 3.04, 95% CI 1.46-6.34), with an incidence rate of 11.7 per 10,000 person-years. In patients over 60 years of age, a prominent risk of hematological malignancies was observed at a follow-up of more than 3 years after the index date (aHR 3.93, 95% CI 1.60-9.65). A history of NTS is associated with the risk of subsequent hematological malignancies in Taiwanese subjects older than 60.

Hospital-Treated Infections and Increased Risk of Two EBV-Related Malignancies: A Nested Case-Control Study

BACKGROUND

To assess the association of hospital-treated infections with the subsequent risk of two Epstein-Barr virus (EBV)-related malignancies, namely Hodgkin's lymphoma (HL) and nasopharyngeal carcinoma (NPC).

METHODS

We performed a nested case-control study based on several national registers in Sweden. Cases were individuals newly diagnosed with HL or NPC during 1994-2016 in Sweden, according to the Swedish Cancer Register. For each case, we randomly selected five controls individually matched to the case on sex and year of birth from the general Swedish population. Hospital-treated infections (i.e., infections requiring either inpatient or outpatient hospital care) were identified from the Swedish Patient Register. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of HL and NPC, in relation to hospital-treated infections, after adjustment for age, sex, calendar period, educational achievement, and region of residence.

RESULTS

The study included a total of 890 cases of HL and 306 cases of NPC. A hospital-treated infection three years ago or earlier was associated with a higher risk of HL (OR = 1.49, 95%CI: 1.26-1.75) as well as NPC (OR = 1.36; 95%CI: 1.01-1.83). The positive association was noted for both bacterial and viral infections and primarily for respiratory and skin infections. A monotonous dose-response relationship was found between a number of hospital-treated infections and the risk of HL (p = 0.02) but less compelling for NPC (p = 0.06). Using a 5-year lag time rendered similar results (OR = 1.43, 95%CI: 1.21-1.70 for HL; OR = 1.43, 95%CI: 1.05-1.95 for NPC).

CONCLUSIONS

These findings suggest that infections requiring hospital treatment might contribute to the carcinogenesis of malignancies potentially related to EBV.

Unusually high incidence of polyomavirus JC infection in the higher grade of colorectal cancer tissues in Taiwan

Introduction

The human JC polyomavirus (JCPyV) has been detected in colorectal cancer (CRC) tissues and is suggested to contribute to CRC tumorigenesis. The rearrangement of the JCPyV regulatory region is supposedly associated with CRC development. The progression of CRC involves the stepwise accumulation of mutations. The large tumor antigen (LT) of JCPyV can trigger uncontrolled cell cycle progression by targeting oncogenes, and tumor suppressor genes, and causing chromosome instability. Few studies have focused on the presence of JCPyV DNA in the higher grade of CRC tissues.

Methods

We collected 95 tissue blocks from samples of stages I, II, III, and IV CRC. Nested PCR targeting the regulatory region of the viral genome was performed to determine the presence of JCPyV DNA in the various stages of colorectal cancer tissues.

Results

The nested PCR results showed that the positive rate of JCPyV DNA increased with the progression of CRC stages. The archetypal-like, non-rearrangement genotype of JCPyV with subtle mutations was the major genotype found in CRC samples.

Conclusions

This finding in our study suggests that there may be an association between JCPyV and CRC progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00756-2.

Targeting Stress Erythropoiesis Pathways in Cancer

Cancer-related anemia (CRA) is a common multifactorial disorder that adversely affects the quality of life and overall prognosis in patients with cancer. Safety concerns associated with the most common CRA treatment options, including intravenous iron therapy and erythropoietic-stimulating agents, have often resulted in no or suboptimal anemia management for many cancer patients. Chronic anemia creates a vital need to restore normal erythropoietic output and therefore activates the mechanisms of stress erythropoiesis (SE). A growing body of evidence demonstrates that bone morphogenetic protein 4 (BMP4) signaling, along with glucocorticoids, erythropoietin, stem cell factor, growth differentiation factor 15 (GDF15) and hypoxia-inducible factors, plays a pivotal role in SE. Nevertheless, a chronic state of SE may lead to ineffective erythropoiesis, characterized by the expansion of erythroid progenitor pool, that largely fails to differentiate and give rise to mature red blood cells, further aggravating CRA. In this review, we summarize the current state of knowledge on the emerging roles for stress erythroid progenitors and activated SE pathways in tumor progression, highlighting the urgent need to suppress ineffective erythropoiesis in cancer patients and develop an optimal treatment strategy as well as a personalized approach to CRA management.

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.

Cancer Susceptibility as a Cost of Reproduction and Contributor to Life History Evolution

Reproduction is one of the most energetically demanding life-history stages. As a result, breeding individuals often experience trade-offs, where energy is diverted away from maintenance (cell repair, immune function) toward reproduction. While it is increasingly acknowledged that oncogenic processes are omnipresent, evolving and opportunistic entities in the bodies of metazoans, the associations among reproductive activities, energy expenditure, and the dynamics of malignant cells have rarely been studied. Here, we review the diverse ways in which age-specific reproductive performance (e.g., reproductive aging patterns) and cancer risks throughout the life course may be linked via trade-offs or other mechanisms, as well as discuss situations where trade-offs may not exist. We argue that the interactions between host–oncogenic processes should play a significant role in life-history theory, and suggest some avenues for future research.

Prevalence of Intestinal Helminths among Cancer Patients Who Are under Chemotherapy at the University of Gondar Comprehensive Specialized Hospital Oncology Clinic, Northwest Ethiopia

Background

In developing countries, environmental and personal hygiene is playing a great role in the increasing of intestinal helminth infection. In countries with limited resources and poor hygiene practices, there is a substantial overlap of intestinal helminthic and chronic infections like HIV, TB, and cancer. Intestinal helminths like Ascaris lumbricoides, Trichuris trichiura, and hookworm cause malnutrition and induce a type-2 immune response that could worsen the severity and clinical outcomes of patients with cancer. Our aim was to determine the prevalence of intestinal helminths among cancer patients who are under chemotherapy. Methodology. A prospective cross-sectional study was conducted in volunteer cancer patients. Clinical information were collected from study participants using a structured questioner. Stool sample was collected for parasitological examination. Formol-ether concentration technique was done, and then, two microscopic slides were prepared. Examination was done by two laboratory technicians for the detection of helminths. SPSS version 22 was used for data analysis, and simple descriptive statistical analysis was done for data presentation.

Result

The total study participants were 41, of these 31 (75.6%) were females and 10 (24.4%) were male. Breast cancer and colonic cancer were the highest proportion with the others, 43.9% and 17.1%, respectively. The prevalence of intestinal parasites were 7/41 (17%). Hookworm 3/41(7.3%), Ascaris lumbricoides 3/41(7.3%), and Hymenolepis nana 1/41(2.4%) are the isolated parasite. Conclusions and Recommendations. The prevalence of intestinal helminths in cancer is lower than HIV and DM in the study area. However, the prevalence in these cancer patients is still high and needs deworming and health education for the better management of these cancer patients.

Bacteria-Mediated Oncogenesis and the Underlying Molecular Intricacies: What We Know So Far

Cancers are known to have multifactorial etiology. Certain bacteria and viruses are proven carcinogens. Lately, there has been in-depth research investigating carcinogenic capabilities of some bacteria. Reports indicate that chronic inflammation and harmful bacterial metabolites to be strong promoters of neoplasticity. Helicobacter pylori-induced gastric adenocarcinoma is the best illustration of the chronic inflammation paradigm of oncogenesis. Chronic inflammation, which produces excessive reactive oxygen species (ROS) is hypothesized to cause cancerous cell proliferation. Other possible bacteria-dependent mechanisms and virulence factors have also been suspected of playing a vital role in the bacteria-induced-cancer(s). Numerous attempts have been made to explore and establish the possible relationship between the two. With the growing concerns on anti-microbial resistance and over-dependence of mankind on antibiotics to treat bacterial infections, it must be deemed critical to understand and identify carcinogenic bacteria, to establish their role in causing cancer.

Season, weight, and age, but not transmissible cancer, affect tick loads in the endangered Tasmanian devil

The Tasmanian devil (Sarcophilus harrisii) is a carnivorous marsupial threatened by a transmissible cancer, devil facial tumour disease (DFTD). While we have a good understanding of the effect of the transmissible cancer on its host, little information is available about its potential interactions with ectoparasites. With this study, we aimed to determine the factors driving tick loads in a DFTD affected Tasmanian devil population, using long-term mark-recapture data. We investigated the effect of a range of life history traits (age, weight, sex, body condition) and of DFTD (time since DFTD arrival and presence of tumours) on the ectoparasitic tick load of the devils. Mixed effect models revealed that tick load in Tasmanian devils was primarily driven by season, weight, body condition and age. Young devils had more ticks compared to older or healthier devils. The reduction in Tasmanian devil population size over the past 14 years at the studied site had little effect on tick infestation. We also found that devils infected by DFTD had a similar tick load compared to those free of observable tumours, suggesting no interaction between the transmissible cancer and tick load. Our study highlights seasonality and life cycle as primary drivers of tick infestation in Tasmanian devils and the need for further investigations to integrate devil stress and immune dynamics with ectoparasite counts.

The Anti-DNA Antibodies: Their Specificities for Unique DNA Structures and Their Unresolved Clinical Impact-A System Criticism and a Hypothesis

Systemic lupus erythematosus (SLE) is diagnosed and classified by criteria, or by experience, intuition and traditions, and not by scientifically well-defined etiology(ies) or pathogenicity(ies). One central criterion and diagnostic factor is founded on theoretical and analytical approaches based on our imperfect definition of the term “The anti-dsDNA antibody”. “The anti-dsDNA antibody” holds an archaic position in SLE as a unique classification criterium and pathogenic factor. In a wider sense, antibodies to unique transcriptionally active or silent DNA structures and chromatin components may have individual and profound nephritogenic impact although not considered yet – not in theoretical nor in descriptive or experimental contexts. This hypothesis is contemplated here. In this analysis, our state-of-the-art conception of these antibodies is probed and found too deficient with respect to their origin, structural DNA specificities and clinical/pathogenic impact. Discoveries of DNA structures and functions started with Miescher’s Nuclein (1871), via Chargaff, Franklin, Watson and Crick, and continues today. The discoveries have left us with a DNA helix that presents distinct structures expressing unique operations of DNA. All structures are proven immunogenic! Unique autoimmune antibodies are described against e.g. ssDNA, elongated B DNA, bent B DNA, Z DNA, cruciform DNA, or individual components of chromatin. In light of the massive scientific interest in anti-DNA antibodies over decades, it is an unexpected observation that the spectrum of DNA structures has been known for decades without being implemented in clinical immunology. This leads consequently to a critical analysis of historical and contemporary evidence-based data and of ignored and one-dimensional contexts and hypotheses: i.e. “one antibody - one disease”. In this study radical viewpoints on the impact of DNA and chromatin immunity/autoimmunity are considered and discussed in context of the pathogenesis of lupus nephritis.

A Case of Concurrent Disseminated Coccidioidomycosis and Embryonal Carcinoma When Lice and Fleas Coexist

Coccidioidomycosis (CM) is a fungal infection endemic to the southwestern United States with a wide range of clinical presentations depending on the infected organ systems. Most infections are asymptomatic. Coccidioidomycosis causes a primary pulmonary infection and when symptoms occur, they most often resemble community-acquired pneumonia. One percent of cases disseminate, typically via hematogenous or lymphatic spread. It is in these cases that more severe symptoms may present and potentially overlap with those characteristics of other systemic illnesses. This is a case of CM disseminated to lymph nodes in a 24-year-old man with concomitant metastatic embryonal carcinoma. It is difficult to identify the primary etiology for many components of this patient's presentation, including diffuse lymphadenopathy and multiple pulmonary nodules. Furthermore, the relationship between these 2 concurrent disease processes is not entirely clear. Factors that may contribute include the well-known phenomenon of locus minoris resistentiae (LMR) or potentially a shared immune failure between infectious organisms and malignant cells.

On the need for integrating cancer into the One Health perspective

Recent pandemics have highlighted the urgency to connect disciplines studying animal, human, and environment health, that is, the "One Health" concept. The One Health approach takes a holistic view of health, but it has largely focused on zoonotic diseases while not addressing oncogenic processes. We argue that cancers should be an additional key focus in the One Health approach based on three factors that add to the well-documented impact of humans on the natural environment and its implications on cancer emergence. First, human activities are oncogenic to other animals, exacerbating the dynamics of oncogenesis, causing immunosuppressive disorders in wildlife with effects on host-pathogen interactions, and eventually facilitating pathogen spillovers. Second, the emergence of transmissible cancers in animal species (including humans) has the potential to accelerate biodiversity loss across ecosystems and to become pandemic. It is crucial to understand why, how, and when transmissible cancers emerge and spread. Third, translating knowledge of tumor suppressor mechanisms found across the Animal Kingdom to human health offers novel insights into cancer prevention and treatment strategies.

Helicobacter pylori co-infection with Epstein-Barr virus and the risk of developing gastric adenocarcinoma at an early age: Observational study infectious agents and cancer

Background

Gastric cancer (GC) is one of the leading causes of morbidity and mortality worldwide. The onset and progression of gastric cancer are attributed to numerous triggers, these triggers may be infection of the gastric epithelium by Helicobacter pylori (H. pylori), or by Epstein-Barr virus (EBV). Both agents can establish a lifelong persistent infection in the host, leading to chronic inflammation, which also contributes to cancer development. Objective: The objective of this study is to present the status of co-infection with H. pylori and EBV and the risk of developing adenocarcinoma at an early age in the population of Grand Casablanca.

Methods

In this study, 100 gastric tissue samples from patients with gastric cancer were examined for detection of H. pylori and EBV in tumor tissue using PCR techniques, and the clinical relevance was statistically analyzed.

Results

Results revealed an individual Epstein-Barr virus (EBV) infection observed in (40 %) of gastric carcinoma cases. Furthermore, the frequency of EBV infection was significantly different with intestinal and diffuse gastric cancer types [15 % vs. 85 %; <0.05]. The prevalence of individual H. pylori infections was 34 %, while the frequency of co-infection was 16 %. Moreover, no significant association was found between co-infection and sex, tumor grade, stage, and lymph node metastasis, but there was a significant association between co-infection and the age of GC patients.

Conclusion

Thus understanding the status of co-infection could clarify the process of gastric carcinogenesis, and application of this knowledge for clinical purposes could facilitate diagnosis, risk management, and prevention.

Determination of the frequency of H. pylori and EBV infections

Correlation between co-infection and age of gastric cancer patients

Evaluation of the clinicopathological features associated with the presence of infectious agents.

Effects of infections on the pathogenesis of cancer

Several studies have shown an inverse relationship between acute infections and cancer development. On the other hand, there is a growing evidence that chronic infections may contribute significantly to the carcinogenesis. Factors responsible for increased susceptibility to infections may include modifications of normal defence mechanisms or impairment of host immunity due to altered immune function, genetic polymorphisms, ageing and malnourishment. Studies have demonstrated that children exposed to febrile infectious diseases show a subsequent reduced risk for ovarian cancer, melanoma and many other cancers, while common acute infections in adults are associated with reduced risks for melanoma, glioma, meningioma and multiple cancers. Chronic inflammation associated with certain infectious diseases has been suggested as a cause for the development of tumours. Mechanisms of carcinogenesis due to infections include cell proliferation and DNA replication by mitogen-activated protein kinase pathway, production of toxins that affect the cell cycle and lead to abnormal cell growth and inhibition of apoptosis. This review was aimed to summarize the available evidence on acute infections as a means of cancer prevention and on the role of chronic infections in the development and progression of cancer.

Identifying key questions in the ecology and evolution of cancer

The application of evolutionary and ecological principles to cancer prevention and treatment, as well as recognizing cancer as a selection force in nature, has gained impetus over the last 50 years. Following the initial theoretical approaches that combined knowledge from interdisciplinary fields, it became clear that using the eco-evolutionary framework is of key importance to understand cancer. We are now at a pivotal point where accumulating evidence starts to steer the future directions of the discipline and allows us to underpin the key challenges that remain to be addressed. Here, we aim to assess current advancements in the field and to suggest future directions for research. First, we summarize cancer research areas that, so far, have assimilated ecological and evolutionary principles into their approaches and illustrate their key importance. Then, we assembled 33 experts and identified 84 key questions, organized around nine major themes, to pave the foundations for research to come. We highlight the urgent need for broadening the portfolio of research directions to stimulate novel approaches at the interface of oncology and ecological and evolutionary sciences. We conclude that progressive and efficient cross-disciplinary collaborations that draw on the expertise of the fields of ecology, evolution and cancer are essential in order to efficiently address current and future questions about cancer.

The potential role of nontyphoidal salmonellosis in gastric cancer: a nationwide matched cohort study

BACKGROUND

The research is to explore the association between nontyphoidal salmonellosis (NTS) and subsequent gastric cancer.

METHODS

We conducted a retrospective study by analyzing hospitalization dataset from the National Health Insurance Research Database in Taiwan. Patients aged 20 years and older with NTS (n = 9 097) admitted between January 1, 2000, and December 31, 2012, were enrolled and followed up until December 31, 2013. The primary outcome was the incidence of gastric cancer. Cox proportional hazards regression was used to estimate the risk of malignancy, accounting for the competing risk of death. In addition, we conducted a sensitivity analysis by propensity score matching and exclusion of malignancy within 1 year observation to minimize measurable confounding and protopathic bias. Negative controls were applied to examine the presence of possible unmeasured confounders in the study.

RESULTS

The study included 18 194 patients (9097 in each NTS and non-NTS group). The median follow-up time was 7 years. The incidence density rate of gastric cancer was 0.72 per 1000 person-years for the NTS group and 0.40 per 1000 person-years for the non-NTS group. The NTS group had a modestly higher risk of gastric cancer (aHR, 2.02; 95% CI 1.18-3.45) than the non-NTS group. The sensitivity analyses revealed consistent results.

CONCLUSIONS

Patients with NTS are associated with increased risk of subsequent gastric cancer compared with non-NTS patients. Future research is needed to examine whether NTS is parallel, reactive or causative to gastric cancer.

SOX1 Is a Backup Gene for Brain Neurons and Glioma Stem Cell Protection and Proliferation

Failed neuroprotection leads to the initiation of several diseases. SOX1 plays many roles in embryogenesis, oncogenesis, and male sex determination, and can promote glioma stem cell proliferation, invasion, and migration due to its high expression in glioblastoma cells. The functional versatility of the SOX1 gene in malignancy, epilepsy, and Parkinson's disease, as well as its adverse effects on dopaminergic neurons, makes it an interesting research focus. Hence, we collate the most important discoveries relating to the neuroprotective effects of SOX1 in brain cancer and propose hypothesis worthy of SOX1's role in the survival of senescent neuronal cells, its roles in fibroblast cell proliferation, and cell fat for neuroprotection, and the discharge of electrical impulses for homeostasis. Increase in electrical impulses transmitted by senescent cells affects the synthesis of neurotransmitters, which will modify the brain cell metabolism and microenvironment.

Pseudomonas aeruginosa Infection Impairs NKG2D-Dependent NK Cell Cytotoxicity through Regulatory T-Cell Activation

Natural killer (NK) cells play a key role in both antibacterial and antitumor immunity. Pseudomonas aeruginosa infection has already been reported to alter NK cell functions. We studied in vitro the effect of P. aeruginosa on NK cell cytotoxic response (CD107a membrane expression) to a lymphoma cell line. Through positive and negative cell sorting and adoptive transfer, we determined the influence of monocytes, lymphocytes, and regulatory T cells (Treg) on NK cell function during P. aeruginosa infection. We also studied the role of the activating receptor natural killer group 2D (NKG2D) in NK cell response to B221. We determined that P. aeruginosa significantly altered both cytotoxic response to B221 and NKG2D expression on NK cells in a Treg-dependent manner and that the NKG2D receptor was involved in NK cell cytotoxic response to B221. Our results also suggested that during P. aeruginosa infection, monocytes participated in Treg-mediated NK cell alteration. In conclusion, P. aeruginosa infection impairs NK cell cytotoxicity and alters antitumor immunity. These results highlight the strong interaction between bacterial infection and immunity against cancer.

Autoimmunity and SLE: Factual and Semantic Evidence-Based Critical Analyses of Definitions, Etiology, and Pathogenesis

One cannot discuss anti-dsDNA antibodies and lupus nephritis without discussing the nature of Systemic lupus erythematosus (SLE). SLE is insistently described as a prototype autoimmune syndrome, with anti-dsDNA antibodies as a central biomarker and a pathogenic factor. The two entities, "SLE" and "The Anti-dsDNA Antibody," have been linked in previous and contemporary studies although serious criticism to this mutual linkage have been raised: Anti-dsDNA antibodies were first described in bacterial infections and not in SLE; later in SLE, viral and parasitic infections and in malignancies. An increasing number of studies on classification criteria for SLE have been published in the aftermath of the canonical 1982 American College of Rheumatology SLE classification sets of criteria. Considering these studies, it is surprising to observe a nearby complete absence of fundamental critical/theoretical discussions aimed to explain how and why the classification criteria are linked in context of etiology, pathogenicity, or biology. This study is an attempt to prioritize critical comments on the contemporary definition and classification of SLE and of anti-dsDNA antibodies in context of lupus nephritis. Epidemiology, etiology, pathogenesis, and measures of therapy efficacy are implemented as problems in the present discussion. In order to understand whether or not disparate clinical SLE phenotypes are useful to determine its basic biological processes accounting for the syndrome is problematic. A central problem is discussed on whether the clinical role of anti-dsDNA antibodies from principal reasons can be accepted as a biomarker for SLE without clarifying what we define as an anti-dsDNA antibody, and in which biologic contexts the antibodies appear. In sum, this study is an attempt to bring to the forum critical comments on the contemporary definition and classification of SLE, lupus nephritis and anti-dsDNA antibodies. Four concise hypotheses are suggested for future science at the end of this analytical study.

Predation shapes the impact of cancer on population dynamics and the evolution of cancer resistance

Cancer is a widespread disease that affects most of the metazoans. However, cancer development is a slow process and, long before causing the death of the individual, may weaken organisms' capacities and impair their interactions with other species. Yet, the impact of cancer development on biotic interactions, and over the dynamics of the whole ecosystem, is still largely unexplored. As well, the feedback of altered biotic interactions on the evolution of resistance against cancer in the context of community ecology has not been investigated. From this new perspective, we theoretically investigate how cancer can challenge expected interaction outcomes in a predator-prey model system, and how, in return, these altered interaction outcomes could affect evolution of resistance mechanism against cancer. First, we demonstrate a clear difference between prey and predator vulnerability to cancer, with cancer having a limited impact on prey populations. Second, we show that biotic interactions can surprisingly lead to a null or positive effect of cancer on population densities. Finally, our evolutionary analysis sheds light on how biotic interactions can lead to diverse resistance levels in predator populations. While its role in ecosystems is mostly unknown, we demonstrate that cancer in wildlife is an important ecological and evolutionary force to consider.

The role of innate immunity in the protection conferred by a bacterial infection against cancer: study of an invertebrate model

All multicellular organisms are exposed to a diversity of infectious agents and to the emergence and proliferation of malignant cells. The protection conferred by some infections against cancer has been recently linked to the production of acquired immunity effectors such as antibodies. However, the evolution of innate immunity as a mechanism to prevent cancer and how it is jeopardized by infections remain poorly investigated. Here, we explored this question by performing experimental infections in two genetically modified invertebrate models (Drosophila melanogaster) that develop invasive or non-invasive neoplastic brain tumors. After quantifying tumor size and antimicrobial peptide gene expression, we found that Drosophila larvae infected with a naturally occurring bacterium had smaller tumors compared to controls and to fungus-infected larvae. This was associated with the upregulation of genes encoding two antimicrobial peptides-diptericin and drosomycin-that are known to be important mediators of tumor cell death. We further confirmed that tumor regression upon infection was associated with an increase in tumor cell death. Thus, our study suggests that infection could have a protective role through the production of antimicrobial peptides that increase tumor cell death. Finally, our study highlights the need to understand the role of innate immune effectors in the complex interactions between infections and cancer cell communities in order to develop innovative cancer treatment strategies.

The TLR4/ERK/PD‑L1 axis may contribute to NSCLC initiation

Infection and inflammation serve an important role in tumor development. Toll-like receptor 4 (TLR4) is a pivotal component of the innate and adaptive immune response during infection and inflammation. Programmed-death ligand 1 (PD-L1) is hypothesized as an important factor for non-small cell lung cancer (NSCLC) immune escape. In the present study, the relationship between TLR4 and PD-L1, in addition to the associated molecular mechanism, were investigated. TLR4 and PD-L1 expression in lung cancer tissues were detected using immunohistochemistry, whilst overall patient survival was measured using the Kaplan-Meier method. The A549 cell line stimulated using lipopolysaccharide (LPS) was applied as the in vitro inflammatory NSCLC model. Associated factors were investigated using reverse transcription-quantitative PCR and western blotting. Lung cancer tissues exhibited increased PD-L1 and TLR4 levels compared with those of adjacent para-cancerous tissues, where there was a positive correlation between TLR4 and PD-L1 expression. In addition, increased expression of these two proteins was found to be linked with poorer prognoses. Following the stimulation of A549 cells with LPS, TLR4 and PD-L1 expression levels were revealed to be upregulated in a dose-dependent manner, where the ERK and PI3K/AKT signaling pathways were found to be activated. Interestingly, in the presence of inhibitors of these two pathways aforementioned, upregulation of PD-L1 expression was only inhibited by the MEK inhibitor PD98059, which can inhibit ERK activity. These data suggested that the ERK signaling pathway is necessary for the TLR4/PD-L1 axis. In conclusion, data from the present study suggest that TLR4 and PD-L1 expression can serve as important prognostic factors for NSCLC, where TLR4 activation may induce PD-L1 expression through the ERK signaling pathway.

Recent Advances in Peptide-Based Approaches for Cancer Treatment

BACKGROUND

Peptide-based pharmaceuticals have recently experienced a renaissance due to their ability to fill the gap between the two main classes of available drugs, small molecules and biologics. Peptides combine the high potency and selectivity typical of large proteins with some of the characteristic advantages of small molecules such as synthetic accessibility, stability and the potential of oral bioavailability.

METHODS

In the present manuscript we review the recent literature on selected peptide-based approaches for cancer treatment, emphasizing recent advances, advantages and challenges of each strategy.

RESULTS

One of the applications in which peptide-based approaches have grown rapidly is cancer therapy, with a focus on new and established targets. We describe, with selected examples, some of the novel peptide-based methods for cancer treatment that have been developed in the last few years, ranging from naturally-occurring and modified peptides to peptidedrug conjugates, peptide nanomaterials and peptide-based vaccines.

CONCLUSION

This review brings out the emerging role of peptide-based strategies in oncology research, critically analyzing the advantages and limitations of these approaches and the potential for their development as effective anti-cancer therapies.

The Binary Classification Of Chronic Diseases

Acute diseases start with an insult and end when insult disappears. If the trauma induces an immune reaction (which happens in most cases), this reaction must be terminated with some type of resolution mechanism, when the cause of the trauma ceases. Chronicity develops if insult is permanent or if the resolution mechanism is defective. Another way to reach disease chronicity is a positive feedback loop, whereby the immune reaction activates an internal, insult-like reaction. A distinction between chronic states characterized by a persistent, low suppressive effect and those characterized by a persistent, high suppressive effect of regulatory T cells (Treg), is proposed. This two-class division represents two ways to reach chronicity: (a) by maintaining inflammatory reaction long after insult disappears ("low Treg"), or (b) by suppressing inflammatory reaction prior to the disappearance of insult ("high Treg"). This two-class division may explain the strong association between certain pathogens and cancer, on one hand, and between several other pathogens and autoimmunity, on the other hand. The weak association between autoimmune diseases and HIV infection and the relatively weak association between autoimmune diseases and cancer may be elucidated as well. In addition, the model rationalizes why immune-modulating drugs, which are effective in cancer, are also effective in "high Treg" viral infections, while corticosteroids, which are generally effective in autoimmune diseases, are also effective in other "low Treg" diseases (such as asthma, atopic dermatitis, and "low Treg" infections) but are not effective in solid malignancies and "high Treg" infections. Moreover, the model expounds why certain bacteria inhibit tumor growth and why these very bacteria induce autoimmune diseases.

Genetic diversity, inbreeding and cancer

Genetic diversity is essential for adaptive capacities, providing organisms with the potential of successfully responding to intrinsic and extrinsic challenges. Although a clear reciprocal link between genetic diversity and resistance to parasites and pathogens has been established across taxa, the impact of loss of genetic diversity by inbreeding on the emergence and progression of non-communicable diseases, such as cancer, has been overlooked. Here we provide an overview of such associations and show that low genetic diversity and inbreeding associate with an increased risk of cancer in both humans and animals. Cancer being a multifaceted disease, loss of genetic diversity can directly (via accumulation of oncogenic homozygous mutations) and indirectly (via increased susceptibility to oncogenic pathogens) impact abnormal cell emergence and escape of immune surveillance. The observed link between reduced genetic diversity and cancer in wildlife may further imperil the long-term survival of numerous endangered species, highlighting the need to consider the impact of cancer in conservation biology. Finally, the somewhat incongruent data originating from human studies suggest that the association between genetic diversity and cancer development is multifactorial and may be tumour specific. Further studies are therefore crucial in order to elucidate the underpinnings of the interactions between genetic diversity, inbreeding and cancer.

Childhood infectious diseases and risk of non-Hodgkin's lymphoma according to the WHO classification: A reanalysis of the Italian multicenter case-control study

Since 1960, incidence of non-Hodgkin's lymphoma (NHL) has been increasing in most industrialized countries, but causes of this trend remain unclear. A role of the decreased exposure to infectious agents during childhood has been proposed. Our study evaluates the association between common childhood infectious diseases and the risk of NHL and its major subtypes by a reanalysis of the Italian multicenter case-control study. After exclusion of next-of-kin interviews, 1,193 cases, diagnosed between 1990 and 1993, and 1,708 population-based controls were included in the analyses. OR estimates were obtained by logistic regression, adjusting for gender, age, residence area, education, smoking habit and exposure to radiations, pesticides and aromatic hydrocarbons. Among B-cell lymphomas (n = 1,102) an inverse association was observed for rubella (OR = 0.80, 95% CI: 0.65-0.99), pertussis (OR = 0.74, 95% CI: 0.62-0.88) and any infection (OR = 0.75, 95% CI: 0.61-0.93). A negative trend by number of infections was observed, which was more evident among mature B-cell lymphoma (OR = 0.66 for three infections or more, 95% CI: 0.48-0.90). Our results indicate a potential protective role of common childhood infections in the etiology of B-cell NHL.

Polymeric Micellar Formulation Enhances Antimicrobial and Anticancer Properties of Salinomycin

PURPOSE

Salinomycin (SAL) is a polyether compound that exhibits strong antimicrobial as well as anticancer activity. Nanomedicine has been at the forefront of drug delivery research with the aim of increasing the efficacy, specificity and reduce toxicity of drugs. There is an intersection between infection and cancer, and cancer patients are prone to bacterial infections. In this study, polymeric micelles were prepared using Pluronic® F127 (PM) to encapsulate SAL (PM_SAL) with the view of enhancing antimicrobial and anticancer activity.

METHODS

A Quality by Design (QbD) approach was utilized to synthesize PM_SAL, and nanoformulation activity was determined against bacterial (S. aureus, MRSA and E. coli). Effects on cancer cell line A549, i.e. cell viability, prevention of P-gp efflux, vimentin expression, effects on migratory ability of A549 cells. Anticancer activity was determined by ability to eradicate cancer stem-like cells.

RESULTS

PM_SAL demonstrated only efficacy against MRSA, being even higher than that obtained with SAL. In A549 cells, a 15-fold increase in P-gp's expression as well as a significant decrease of the cell's migration, was observed.

CONCLUSIONS

PM_SAL can interfere with the oncogenic protein VIM, involved in the crucial mechanisms EMT, downregulating its expression. Altogether data obtained indicates that this antibiotic and the developed polymeric micelle system is a very promising inhibitor of tumor cell growth.

Association between Helicobacter pylori, Epstein-Barr virus, human papillomavirus and gastric adenocarcinomas

AIM

To correlate Helicobacter pylori (H. pylori), Epstein-Barr virus (EBV) and human papillomavirus (HPV) with gastric cancer (GC) cases in Pará State, Brazil.

METHODS

Tissue samples were obtained from 302 gastric adenocarcinomas. A rapid urease test was used to detect the presence of H. pylori, and the presence of the cagA gene in the HP-positive samples was confirmed by PCR. An RNA in situ hybridization test designed to complement Eber1 RNA was used to detect the presence of EBV in the samples, and the L1 region of HPV was detected using nested PCR. Positive HPV samples were genotyped and analyzed for E6 and E7 viral gene expression. Infections were also correlated with the clinical and pathological characteristics of the patients.

RESULTS

The majority of the 302 samples analyzed were obtained from men (65%) aged 55 years or older (67%) and were classified as the intestinal subtype (55%). All three pathogens were found in the samples analyzed in the present study (H. pylori: 87%, EBV: 20%, HPV: 3%). Overall, 78% of the H. pylori-positive (H. pylori⁺) samples were cagA+ (H. pylori-cagA⁺), and there was an association between the cytotoxic product of this gene and EBV. Coinfections of H. pylori-cagA⁺ and EBV were correlated with the most advanced tumor stages. Although only 20% of the tumors were positive for EBV, infection with this virus was associated with distant metastasis. Only the HPV 16 and 18 strains were found in the samples, although no expression of the E6 and E7 oncoproteins was detected. The fundus of the stomach was the region least affected by the pathogens.

CONCLUSION

HPV was not involved in gastric tumorigenesis. Prophylactic and therapeutic measures against H. pylori and EBV may prevent the development of GC, especially the more aggressive forms.

Personal history of infections and immunotherapy: Unexpected links and possible therapeutic opportunities

The recent breakthroughs in the understanding of tumor immune biology have given rise to a new generation of immunotherapies, harnessing the immune system to eliminate tumors. As the typology and frequency of encountered infections are susceptible to shape the immune system, it could also impact the efficiency of immunotherapy. In this review, we report evidences for an indirect link between personal history of infection and different strategies of immunotherapy. In the current context of interest rise for personalized medicine, we discuss the potential medical applications of considering personal history of infection to design immunotherapeutic strategies.

Childhood infectious diseases and risk of multiple myeloma: an analysis of the Italian multicentre case-control study

Common childhood infectious diseases have been associated with a reduced risk of following haematopoietic malignancies, but investigations on multiple myeloma (MM) are scarce. Information about 213 MM cases and 1128 healthy controls were obtained from a multicentre population-based Italian case-control study. The association between chickenpox, measles, mumps, pertussis and rubella and the MM risk was estimated by unconditional logistic regression, adjusting for age, gender and residence area. No association was found between MM risk and any considered infectious disease. The number of infections was slightly inversely associated with the risk of MM, but statistical significance was not reached (OR 0.87, 95% CI 0.55-1.4 for 1-2 diseases vs. none and OR 0.68, 95% CI 0.41-1.1 for 3-5 diseases, respectively, P = 0.131). We did not find a clear evidence that common infections during childhood are associated with the subsequent risk of developing MM.

Echinococcus granulosus: Cure for Cancer Revisited

Whereas a number of parasites are well recognized risk factors for a number of different cancers in mammalian hosts, there is limited information on the ability of parasitic organisms to induce anticancer effects. There are conflicting reports that echinococcosis, caused by the canine tapeworm Echinococcus granulosus, can decrease or increase cancer risk. This review considers both indirect anticancer effects as the result of adaptive immunity generated against certain echinococcal antigens and the direct effect of molecules released by E. granulosus whose activity directly inhibits cancer cell migration and growth. In conclusion, E. granulosus probably secretes molecules that can be developed as anticancer therapeutics in future.

Ancient oncogenesis, infection and human evolution

The recent discovery that malignant neoplastic lesions date back nearly 2 million years ago not only highlights the antiquity of cancer in the human lineage, but also provides remarkable insight into ancestral hominin disease pathology. Using these Early Pleistocene examples as a point of departure, we emphasize the prominent role of viral and bacterial pathogens in oncogenesis and evaluate the impact of pathogens on human evolutionary processes in Africa. In the Shakespearean vernacular "what's past is prologue," we highlight the significance of novel information derived from ancient pathogenic DNA. In particular, and given the temporal depth of human occupation in sub-Saharan Africa, it is emphasized that the region is ideally positioned to play a strategic role in the discovery of ancient pathogenic drivers of not only human mortality, but also human evolution. Ancient African pathogen genome data can provide novel revelations concerning human-pathogen coevolutionary processes, and such knowledge is essential for forecasting the ways in which emerging zoonotic and increasingly transmissible diseases might influence human demography and longevity in the future.