Role of bacteria in carcinogenesis, with special reference to carcinoma of the gallbladder

The complex effects of modern oncogenic environments on the fitness, evolution and conservation of wildlife species

Growing evidence indicates that human activities are causing cancer rates to rise in both human and wildlife populations. This is due to the inability of ancestral anti-cancer defences to cope with modern environmental risks. The evolutionary mismatch between modern oncogenic risks and evolved cancer defences has far-reaching effects on various biological aspects at different timeframes, demanding a comprehensive study of the biology and evolutionary ecology of the affected species. Firstly, the increased activation of anti-cancer defences leads to excessive energy expenditure, affecting other biological functions and potentially causing health issues like autoimmune diseases. Secondly, tumorigenesis itself can impact important fitness-related parameters such as competitiveness, predator evasion, resistance to parasites, and dispersal capacity. Thirdly, rising cancer risks can influence the species' life-history traits, often favoring early reproduction to offset fitness costs associated with cancer. However, this strategy has its limits, and it may not ensure the sustainability of the species if cancer risks continue to rise. Lastly, some species may evolve additional anti-cancer defences, with uncertain consequences for their biology and future evolutionary path. In summary, we argue that the effects of increased exposure to cancer-causing substances on wildlife are complex, ranging from immediate responses to long-term evolutionary changes. Understanding these processes, especially in the context of conservation biology, is urgently needed.

Interplay between the Human Microbiome and Biliary Tract Cancer: Implications for Pathogenesis and Therapy

Biliary tract cancer, encompassing intrahepatic and extrahepatic cholangiocarcinoma as well as gallbladder carcinoma, stands as a prevalent malignancy characterized by escalating incidence rates and unfavorable prognoses. The onset of cholangiocarcinoma involves a multitude of risk factors and could potentially be influenced by microbial exposure. The human microbiome, encompassing the entirety of human microbial genetic information, assumes a pivotal role in regulating key aspects such as host digestion, absorption, immune responses, and metabolism. The widespread application of next-generation sequencing technology has notably propelled investigations into the intricate relationship between the microbiome and diseases. An accumulating body of evidence strongly suggests a profound interconnection between biliary tract cancer and the human microbiome. This article critically appraises the existing evidence pertaining to the microbiome milieu within patients afflicted by biliary tract cancer. Furthermore, it delves into potential mechanisms through which dysregulation of the human microbiome could contribute to the advancement of biliary tract cancer. Additionally, the article expounds on its role in the context of chemotherapy and immunotherapy for biliary tract cancer.

Receptor of advanced glycation end-products axis and gallbladder cancer: A forgotten connection that we should reconsider

Compelling evidence derived from clinical and experimental research has demonstrated the crucial contribution of chronic inflammation in the development of neoplasms, including gallbladder cancer. In this regard, data derived from clinical and experimental studies have demonstrated that the receptor of advanced glycation end-products (RAGE)/AGEs axis plays an important role in the onset of a crucial and long-lasting inflammatory milieu, thus supporting tumor growth and development. AGEs are formed in biological systems or foods, and food-derived AGEs, also known as dietary AGEs are known to contribute to the systemic pool of AGEs. Once they bind to RAGE, the activation of multiple and crucial signaling pathways are triggered, thus favoring the secretion of several proinflammatory cytokines also involved in the promotion of gallbladder cancer invasion and migration. In the present review, we aimed to highlight the relevance of the association between high dietary AGEs intakes and high risk for gallbladder cancer, and emerging data supporting that dietary intervention to reduce gallbladder cancer risk is a very attractive approach that deserves much more research efforts.

A systematic review on omics data (metagenomics, metatranscriptomics, and metabolomics) in the role of microbiome in gallbladder disease

Microbiotas are the range of microorganisms (mainly bacteria and fungi) colonizing multicellular, macroscopic organisms. They are crucial for several metabolic functions affecting the health of the host. However, difficulties hamper the investigation of microbiota composition in cultivating microorganisms in standard growth media. For this reason, our knowledge of microbiota can benefit from the analysis of microbial macromolecules (DNA, transcripts, proteins, or by-products) present in various samples collected from the host. Various omics technologies are used to obtain different data. Metagenomics provides a taxonomical profile of the sample. It can also be used to obtain potential functional information. At the same time, metatranscriptomics can characterize members of a microbiome responsible for specific functions and elucidate genes that drive the microbiotas relationship with its host. Thus, while microbiota refers to microorganisms living in a determined environment (taxonomy of microorganisms identified), microbiome refers to the microorganisms and their genes living in a determined environment and, of course, metagenomics focuses on the genes and collective functions of identified microorganisms. Metabolomics completes this framework by determining the metabolite fluxes and the products released into the environment. The gallbladder is a sac localized under the liver in the human body and is difficult to access for bile and tissue sampling. It concentrates the bile produced in the hepatocytes, which drains into bile canaliculi. Bile promotes fat digestion and is released from the gallbladder into the upper small intestine in response to food. Considered sterile originally, recent data indicate that bile microbiota is associated with the biliary tract’s inflammation and carcinogenesis. The sample size is relevant for omic studies of rare diseases, such as gallbladder carcinoma. Although in its infancy, the study of the biliary microbiota has begun taking advantage of several omics strategies, mainly based on metagenomics, metabolomics, and mouse models. Here, we show that omics analyses from the literature may provide a more comprehensive image of the biliary microbiota. We review studies performed in this environmental niche and focus on network-based approaches for integrative studies.

Evaluation of Enterococcus faecalis, Lactobacillus acidophilus, and Lactobacillus plantarum in Biopsy Samples of Colorectal Cancer and Polyp Patients Compared to Healthy People

Background: Colorectal cancer (CRC) is one of the leading causes of death in both men and women worldwide. According to different studies, infectious agents or microbiota dysbiosis can play a role in CRC progression. Objective: This study aimed to evaluate the prevalence of Enterococcus faecalis, Lactobacillus acidophilus, and Lactobacillus plantarum in people with polyps or CRC compared to healthy individuals. Methods: In this study, 60 biopsy samples were collected from three groups, including patients with CRC, polyps, and healthy people. The genomic DNA was extracted from the collected samples and amplified by polymerase chain reaction (PCR) to detect E. faecalis, L. acidophilus, and L. plantarum. In the next step, quantitative Real-Time PCR was used to evaluate the copy number of the bacteria in the studied groups. Results: There was no statistically significant difference between the studied groups regarding age and gender (P > 0.05). The mean number of E. faecalis was higher in patients with CRC than in patients with polyps and healthy individuals (P < 0.05). Also, the mean numbers of L. acidophilus and L. plantarum were higher in healthy individuals than in patients with polyps and CRC (P < 0.05). Conclusions: Our findings indicate that L. acidophilus and L. plantarum in people with a family history of CRC and patients with polyps may effectively prevent or reduce CRC progression.

Skin Cancer-Associated S. aureus Strains Can Induce DNA Damage in Human Keratinocytes by Downregulating DNA Repair and Promoting Oxidative Stress

Actinic keratosis (AK) is a premalignant lesion, common on severely photodamaged skin, that can progress over time to cutaneous squamous cell carcinoma (SCC). A high bacterial load of Staphylococcus aureus is associated with AK and SCC, but it is unknown whether this has a direct impact on skin cancer development. To determine whether S. aureus can have cancer-promoting effects on skin cells, we performed RNA sequencing and shotgun proteomics on primary human keratinocytes after challenge with sterile culture supernatant ('secretome') from four S. aureus clinical strains isolated from AK and SCC. Secretomes of two of the S. aureus strains induced keratinocytes to overexpress biomarkers associated with skin carcinogenesis and upregulated the expression of enzymes linked to reduced skin barrier function. Further, these strains induced oxidative stress markers and all secretomes downregulated DNA repair mechanisms. Subsequent experiments on an expanded set of lesion-associated S. aureus strains confirmed that exposure to their secretomes led to increased oxidative stress and DNA damage in primary human keratinocytes. A significant correlation between the concentration of S. aureus phenol soluble modulin toxins in secretome and the secretome-induced level of oxidative stress and genotoxicity in keratinocytes was observed. Taken together, these data demonstrate that secreted compounds from lesion-associated clinical isolates of S. aureus can have cancer-promoting effects in keratinocytes that may be relevant to skin oncogenesis.

A perspective review on impact and molecular mechanism of environmental carcinogens on human health

Cancer is one of the leading causes of death all around the world. It is a group of diseases characterized by abnormal and uncontrollable division of cells leading to severe health conditions and fatality if remains undiagnosed till later stages. Cancer can be caused due to mutation or sudden alterations by effect of certain external agents. Agents that can cause sudden alterations in the genetic content of an individual are known as mutagens. Mutations can lead to permanent changes in the genetic constituency of an individual and possibly lead to cancer. Mutagenic agents that possess the capacity to induce cancer in humans are called carcinogens. Carcinogens may be naturally present in the environment or generated by anthropogenic activities. However, with the progress in molecular techniques, genetic and/or epigenetic mechanisms of carcinogenesis of a wide range of carcinogens have been elucidated. Present review aims to discuss different types of environmental carcinogens and their respective mechanisms responsible for inducing cancer in humans.

Biliary Migration, Colonization, and Pathogenesis of O. viverrini Co-Infected with CagA+ Helicobacter pylori

Co-infection with the cagA strain of Helicobacter pylori exacerbates the pathology of human liver fluke Opisthorchis viverrini (OV) infection leading to cholangiocarcinoma. However, underlying mechanisms remain unclear. We report a significant increase in cagA-positive and cagA-negative H. pylori in the stomach, blood, bile, and in the OV worms of co-infected Syrian golden hamsters at one hour, three hours, and one month, post-infection, compared to hamsters infected with either OV or H. pylori alone. Except in the worms, H. pylori numbers declined at three months post-infection, particularly in the bile fluid of co-infected animals. Both strains of H. pylori were immunohistochemically detected in the tegument of the worm, as well as in the bile duct epithelium when co-infected with O. viverrine, but not in H. pylori infection alone. Interestingly, only the cagA-positive strain was detected in the gut of the worm. Co-infection between cagA-positive H. pylori and O. viverrini resulted in a more severe biliary pathology and decreased E-cadherin expression in vivo and in vitro than those of the cagA-negative strain. These data suggest that O. viverrini acts as a carrier of cagA-positive H. pylori and co-migrates to the bile ducts, whereas O. viverrini facilitates H. pylori colonization and enhances the biliary pathogenesis and carcinogenesis.

The role of the bacterial microbiome in the treatment of cancer

The human microbiome is defined as the microorganisms that reside in or on the human body, such as bacteria, viruses, fungi, and protozoa, and their genomes. The human microbiome participates in the modulation of human metabolism by influencing several intricate pathways. The association between specific bacteria or viruses and the efficacy of cancer treatments and the occurrence of treatment-related toxicity in cancer patients has been reported. However, the understanding of the interaction between the host microbiome and the cancer treatment response is limited, and the microbiome potentially plays a greater role in the treatment of cancer than reported to date. Here, we provide a thorough review of the potential role of the gut and locally resident bacterial microbiota in modulating responses to different cancer therapeutics to demonstrate the association between the gut or locally resident bacterial microbiota and cancer therapy. Probable mechanisms, such as metabolism, the immune response and the translocation of microbiome constituents, are discussed to promote future research into the association between the microbiome and other types of cancer. We conclude that the interaction between the host immune system and the microbiome may be the basis of the role of the microbiome in cancer therapies. Future research on the association between host immunity and the microbiome may improve the efficacy of several cancer treatments and provide insights into the cause of treatment-related side effects.

Association of Microbial Dysbiosis with Gallbladder Diseases Identified by Bile Microbiome Profiling

BACKGROUND

Cholecystitis is an important risk factor for gallbladder cancer, but the bile microbiome and its association with gallbladder disease has not been investigated fully. We aimed to analyze the bile microbiome in normal conditions, chronic cholecystitis, and gallbladder cancer, and to identify candidate bacteria that play an important role in gallbladder carcinogenesis.

METHODS

We performed metagenome sequencing on bile samples of 10 healthy individuals, 10 patients with chronic cholecystitis, and 5 patients with gallbladder cancer, and compared the clinical, radiological, and pathological characteristics of the participants.

RESULTS

No significant bacterial signal was identified in the normal bile. The predominant dysbiotic bacteria in both chronic cholecystitis and gallbladder cancer were those belonging to the Enterobacteriaceae family. Klebsiella increased significantly in the order of normal, chronic cholecystitis, and gallbladder cancer. Patients with chronic cholecystitis and dysbiotic microbiome patterns had larger gallstones and showed marked epithelial atypia, which are considered as precancerous conditions.

CONCLUSION

We investigated the bile microbiome in normal, chronic cholecystitis, and gallbladder cancer. We suggest possible roles of Enterobacteriaceae, including Klebsiella, in gallbladder carcinogenesis. Our findings reveal a possible link between a dysbiotic bile microbiome and the development of chronic calculous cholecystitis and gallbladder cancer.

Bacterial cyclomodulins: types and roles in carcinogenesis

Various studies confirmed that bacterial infections contribute to carcinogenesis through the excessive accumulation of reactive oxygen species (ROS) and the expression of toxins that disrupt the cell cycle phases, cellular regulatory mechanisms and stimulate the production of tumorigenic inflammatory mediators. These toxins mimic carcinogens which act upon key cellular targets and result in mutations and genotoxicities. The cyclomodulins are bacterial toxins that incur cell cycle modulating effects rendering the expressing bacterial species of high carcinogenic potentiality. They are either cellular proliferating or cell cycle arrest cyclomodulins. Notably, cyclomodulins expressing bacterial species have been linked to different human carcinomas. For instance, Escherichia coli species producing the colibactin were highly prevalent among colorectal carcinoma patients, CagA⁺ Helicobacter pylori species were associated with MALT lymphomas and gastric carcinomas and Salmonella species producing CdtB were linked to hepatobiliary carcinomas. These species stimulated the overgrowth of pre-existing carcinomas and induced hyperplasia in in vivo animal models suggesting a role for the cyclomodulins in carcinogenesis. Wherefore, the prevalence and mode of action of these toxins were the focus of many researchers and studies. This review discusses different types of bacterial cyclomodulins highlighting their mode of action and possible role in carcinogenesis.

Anticancer activity of Helicobacter pylori ribosomal protein (HPRP) with iRGD in treatment of colon cancer

PURPOSE

As the conventional therapeutic approaches were not completely successful in the treatment of colon cancer, there is still a need for finding the most efficient therapeutic agents. Here we investigated the anticancer activity of HPRP-A1 that was derived from the N-terminal region of Helicobacter pylori ribosomal protein L1 (RpL1) alone or in combination with tumor-homing peptide iRGD and 5-Fluorouracil (5FU) on colon cancer cell lines (CT26 and HT29) and isograft models of colon cancer.

METHOD

We assessed the tumor growth inhibitory activity of HPRP-A1 with or without iRGD and 5FU on colon cancer in vitro and in vivo. In the in vitro part, we investigate the effect of HPRP-A1 alone and in combination with iRGD/5FU.

RESULTS

Our results demonstrated that co-administration of HPRP-A1 with iRGD increased the apoptosis, while these two peptides in combination with 5FU increased the intracellular level of p53 that upregulate the pro-apoptotic gene BAX and downregulate the anti-apoptotic gene BCL2. HPRP-A1 blocks the cell cycle progression in G0/G1. Co-administration of two peptides significantly reduced the size and weight of the tumors, while the group that received 5FU in combination with the peptides increased the necrotic and decrease the fibrotic area significantly in the tumor tissues, which also disrupt the oxidant/antioxidant balance.

CONCLUSIONS

Our results indicated that HPRP-A1 could be considered an effective agent toward colon cancer in vitro and in vivo with the ability to enhance the effects of conventional chemotherapy agent 5FU.

Roles of Salmonella typhi and Salmonella paratyphi in Gallbladder Cancer Development

BACKGROUND

Typhoid (Salmonella typhi and paratyphi) carriers and gall bladder cancer (GBC) are endemic in northern India. Results of previous studies about association of typhoid carriers with GBC are inconsistent. We studied antibodies against Salmonella typhi and paratyphi in serum samples of patients with GBC.

METHODS

We performed modified Widal test for antibodies against Salmonella typhi (Vi and O) and Salmonella paratyphi (AO and BO) antigens in patients with GBC (n=100), xanthogranulomatous cholecystitis (XGC, n=24), chronic cholecystitis (CC, n=200) and healthy controls (HC, n=200).

RESULTS

Serum antibodies against Salmonella were more frequently positive in GBC (22%) and XGC (29%), particularly in males in age ≥50 years (GBC: 47% and XGC: 50%) vs. HC (0) (p <0.01). Vi antibody was more common in GBC (13%, OR:9.8) and XGC (8%, OR:5.9) than HC (2%). O antibody was more common in GBC (8%, OR: 8.6) and XGC (8%, OR: 9.0) than HC (1%). O antibody was also more common in males with GBC (12%) than CC (1%) and HC (1%) (P=0.02 and p <0.001, respectively). AO (6%) and BO (4%) antibodies were detected in GBC, particularly in males, than HC (0), (p <0.01). Salmonella antibodies were more frequent in GBC with GS than those without GS (50% vs. 20%, OR=3.94, P=0.01).

CONCLUSIONS

Salmonella carrier state was more common in GBC and XGC, particularly in elderly males than HC. The Vi antibody was more common in GBC and XGC than HC. Salmonella infection was more common in GBC with GS than those without GS.

The Microbiome and Its Implications in Cancer Immunotherapy

Cancer is responsible for ~18 million deaths globally each year, representing a major cause of death. Several types of therapy strategies such as radiotherapy, chemotherapy and more recently immunotherapy, have been implemented in treating various types of cancer. Microbes have recently been found to be both directly and indirectly involved in cancer progression and regulation, and studies have provided novel and clear insights into the microbiome-mediated emergence of cancers. Scientists around the globe are striving hard to identify and characterize these microbes and the underlying mechanisms by which they promote or suppress various kinds of cancer. Microbes may influence immunotherapy by blocking various cell cycle checkpoints and the production of certain metabolites. Hence, there is an urgent need to better understand the role of these microbes in the promotion and suppression of cancer. The identification of microbes may help in the development of future diagnostic tools to cure cancers possibly associated with the microbiome. This review mainly focuses on various microbes and their association with different types of cancer, responses to immunotherapeutic modulation, physiological responses, and prebiotic and postbiotic effects.

Detection of Streptococcus gallolyticus in colorectal cancer and inflammatory bowel disease patients compared to control group in southwest of Iran

There are several pieces of evidence regarding the role of bacteria, such as Streptococcus bovis/gallolyticus in the etiology of gastrointestinal diseases such as colorectal cancer (CRC) and inflammatory bowel disease (IBD). Therefore, the aim of this study was to detect S. gallolyticus subsp. gallolyticus (Sgg) in fecal samples of CRC and IBD patients by culture and molecular methods, in Ahvaz, southwest of Iran. A total of 106 fecal samples were collected from 22 CRC patients, 44 IBD patients, and 40 healthy individuals. The prevalence of Sgg was investigated by culture and polymerase chain reaction (PCR) with specific primers for sodA gene. The results of the stool culture showed that the overall prevalence of Sgg was 9 (13.6%) out of 66 patients. Meanwhile, the number of Sgg isolated from IBD and CRC patients was 7 (15.9%) and 2 (9%), respectively. The bacteria were not isolated from any of the control groups. On the basis of PCR, S. gallolyticus was detected in 24 (36.4%) out of 66 patients. Meanwhile, the number of IBD patients with positive sodA gene was 15 (34.1%) out of 44 cases. In CRC patients, the sodA gene was detected in 9 (40.9%) of 22 cases. Two (5%) of the specimens in the control group had the sodA gene. According to our results, S. gallolyticus subsp. gallolyticus might be involved in CRC and IBD pathogenesis. More investigation with different samples in the various areas might be shaded light on these results.

Genotoxic Effect of Salmonella Paratyphi A Infection on Human Primary Gallbladder Cells

Bacterial infections are increasingly being recognized as risk factors for the development of adenocarcinomas. The strong epidemiological evidence linking Helicobacter pylori infection to stomach cancer has paved the way to the demonstration that bacterial infections cause DNA damage in the host cells, initiating transformation. In this regard, the role of bacterial genotoxins has become more relevant. Salmonella enterica serovars Typhi and Paratyphi A have been clinically associated with gallbladder cancer. By harnessing the stem cell potential of cells from healthy human gallbladder explant, we regenerated and propagated the epithelium of this organ in vitro and used these cultures to model S. Paratyphi A infection. This study demonstrates the importance of the typhoid toxin, encoded only by these specific serovars, in causing genomic instability in healthy gallbladder cells, posing intoxicated cells at risk of malignant transformation.

Carcinoma of the gallbladder (GBC) is the most frequent tumor of the biliary tract. Despite epidemiological studies showing a correlation between chronic infection with Salmonella enterica Typhi/Paratyphi A and GBC, the underlying molecular mechanisms of this fatal connection are still uncertain. The murine serovar Salmonella Typhimurium has been shown to promote transformation of genetically predisposed cells by driving mitogenic signaling. However, insights from this strain remain limited as it lacks the typhoid toxin produced by the human serovars Typhi and Paratyphi A. In particular, the CdtB subunit of the typhoid toxin directly induces DNA breaks in host cells, likely promoting transformation. To assess the underlying principles of transformation, we used gallbladder organoids as an infection model for Salmonella Paratyphi A. In this model, bacteria can invade epithelial cells, and we observed host cell DNA damage. The induction of DNA double-strand breaks after infection depended on the typhoid toxin CdtB subunit and extended to neighboring, non-infected cells. By cultivating the organoid derived cells into polarized monolayers in air-liquid interphase, we could extend the duration of the infection, and we observed an initial arrest of the cell cycle that does not depend on the typhoid toxin. Non-infected intoxicated cells instead continued to proliferate despite the DNA damage. Our study highlights the importance of the typhoid toxin in causing genomic instability and corroborates the epidemiological link between Salmonella infection and GBC.

Dual Role of Bacteria in Carcinoma: Stimulation and Inhibition

Although what unifies the carcinogenic microorganisms has not been determined by multiple studies, the role of bacteria in the development of neoplasms has not been properly elucidated. In this review, we discuss links between the bacterial species and cancer, with focus on immune responses for the stimulation of tumor cells such as induction of inflammation. Finally, we will describe the potential therapeutic strategies of bacteria on target tumors to improve treatment while mitigating adverse reactions. Cancer is a series of genetic changes that transform normal cells into tumor cells. These changes come from several reasons, including smoking, drinking alcohol, sunlight, exposure to chemical or physical factors, and finally chronic infection with microorganisms, including bacteria. In fact, bacterial infections are not carcinogenic, but recently it was discovered that the association between bacteria and cancer is through two mechanisms, the first stimulating chronic inflammation and the second producing carcinogenic metabolites. While bacteria are carcinogenic agents also, they have a dual role eliminating and removing tumor cells. However, the traditional cancer treatments that include chemotherapy, radiotherapy, surgery, and immunotherapy increase the chances of survival, and there are many side effects of these therapies, including the high toxicity of tissues and normal cells, could not penetrate the tumor cells, and resistance of these therapies by tumor cells. Therefore, the world has turned to an alternative solution, which is the use of genetically engineered microorganisms; thus, the use of living bacteria targeting cancerous cells is the unique option to overcome these challenges. Bacterial therapies, whether used alone or combination with chemotherapy, give a positive effect to treat multiple conditions of cancer. Also, bacteria can be used as vectors for drug, gene, or therapy, and this is a great step to treat cancer. Thus, we review the mechanisms underlying the interaction of the microbiota residents with cancer. Cancer-associated bacteria differ from those in healthy human and are linked with gene-expression profile. We also discuss how live bacteria interact with tumor microenvironments to induce tumor regression through colonization and spread. Finally, we provide past and ongoing clinical trials that include bacteria targeting tumors.

Increased risk of incident primary cancer after Staphylococcus aureus bacteremia: A matched cohort study

Susceptibility to infectious disease may be a marker of immunodeficiency caused by unrecognized cancer. To test the hypothesis, the risk of incident primary cancer was estimated among survivors of Staphylococcus aureus bacteremia (SAB) and compared to a random population cohort.Nation-wide population-based matched cohort study. Cases of SAB were identified from a national database and incident primary cancers were ascertained by record linkage. Incidence rate (IR) and ratio (IRR) with 95% confidence interval (CI) of 27 cancers was calculated by Poisson regression.During the first year of follow-up, 165 and 943 incident cases of cancer occurred in the case cohort (n = 12,918 (1.3%)) and the population cohort (n = 117,465 (0.8%)) for an IR of 3.78 (3.22-4.40) and 2.28 (2.14-2.43) per 100,000 person-years. The IRR was 1.65 (1.40-1.95). Of 27 cancers, 7 cancers occurred more frequently amongst cases than controls: cervical cancer (IRR 37.83 (4.23-338.47)), multiple myeloma (IRR 6.31 (2.58-15.44)), leukemia (IRR 4.73 (2.21-10.10)), sarcoma (IRR 4.73 (1.18-18.91)), liver cancer (IRR 3.64 (1.30-10.21)), pancreatic cancer (IRR 2.8 (1.27-6.16)), and urinary tract cancer (IRR 2.58 (1.23-5.39)). Compared to the control population, the risk of cancer was higher for those without comorbidity and with younger age. The overall risk of cancer during 2 to 5 years of follow-up was not increased (IRR 0.99 (95% CI: 0.89-1.11). However, the risk of pharyngeal cancer was increased (IRR 1.88 (1.04-3.39)) and the risk of liver cancer remained increased (IRR 3.93 (2.36-6.55)).The risk of primary incident cancer was 65% higher in the SAB cohort compared to the population cohort during the first year of follow-up and included 7 specific cancers. The risk was higher for those without comorbidity and with younger age. Screening for these specific cancers in selected populations may allow for earlier detection.

Rapamycin Re-Directs Lysosome Network, Stimulates ER-Remodeling, Involving Membrane CD317 and Affecting Exocytosis, in Campylobacter Jejuni-Lysate-Infected U937 Cells

The Gram-negative Campylobacter jejuni is a major cause of foodborne gastroenteritis in humans worldwide. The cytotoxic effects of Campylobacter have been mainly ascribed to the actions of the cytolethal distending toxin (CDT): it is mandatory to put in evidence risk factors for sequela development, such as reactive arthritis (ReA) and Guillain–Barré syndrome (GBS). Several researches are directed to managing symptom severity and the possible onset of sequelae. We found for the first time that rapamycin (RM) is able to largely inhibit the action of C. jejuni lysate CDT in U937 cells, and to partially avoid the activation of specific sub-lethal effects. In fact, we observed that the ability of this drug to redirect lysosomal compartment, stimulate ER-remodeling (highlighted by ER–lysosome and ER–mitochondria contacts), protect mitochondria network, and downregulate CD317/tetherin, is an important component of membrane microdomains. In particular, lysosomes are involved in the process of the reduction of intoxication, until the final step of lysosome exocytosis. Our results indicate that rapamycin confers protection against C. jejuni bacterial lysate insults to myeloid cells.

The scope of viral causation of human cancers: interpreting virus density from an evolutionary perspective

Most known oncogenic viruses of humans use DNA as their genomic material. Research over the past quarter century has revealed that their oncogenicity results largely from direct interference with barriers to oncogenesis. In contrast to viruses that have been accepted causes of particular cancers, candidate viral causes tend to have fewer viral than cellular genomes in the tumours. These low viral loads have caused researchers to conclude that the associated viruses are not primary causes of the associated cancers. Consideration of differential survival, reproduction and infiltration of cells in a tumour suggest, however, that viral loads could be low even when viruses are primary causes of cancer. Resolution of this issue has important implications for human health because medical research tends to be effective at preventing and controlling infectious diseases. Mathematical models may clarify the problem and help guide future research by assessing whether low viral loads are likely outcomes of the differential survival, reproduction, and infiltration of cells in a tumour and, more generally, the extent to which viruses contribute to cancer. This article is part of the theme issue 'Silent cancer agents: multi-disciplinary modelling of human DNA oncoviruses'.

Cho W, Soleimanpour S. Bacteriotherapy in Breast Cancer

Breast cancer is the second most common cause of cancer-related mortality among women around the world. Conventional treatments in the fight against breast cancer, such as chemotherapy, are being challenged regarding their effectiveness. Thus, strategies for the treatment of breast cancer need to be continuously refined to achieve a better patient outcome. We know that a number of bacteria are pathogenic and some are even associated with tumor development, however, recent studies have demonstrated interesting results suggesting some bacteria may have potential for cancer therapy. Therefore, the therapeutic role of bacteria has aroused attention in medical and pharmaceutical studies. Furthermore, genetic engineering has been used in bacterial therapy and may led to greater efficacy with few side effects. Some genetically modified non-pathogenic bacterial species are more successful due to their selectivity for cancer cells but with low toxicity for normal cells. Some live, attenuated, or genetically modified bacterias are capable to multiply in tumors and inhibit their growth. This article aims to review the role of bacteria and their products including bacterial peptides, bacteriocins, and toxins for the treatment of breast cancer.

Studying the effects of several heat-inactivated bacteria on colon and breast cancer cells

A great number of researches over the last years are allocated to know cancer reasons, prevention and treatment strategies. Bacterial infections are one of the promoting factors in cancer development. The present study was carried out to study effects of heat-killed bacteria on cancer cell lines MCF7 and HT-29. To this purpose, four bacterial strains including Salmonella typhi, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa were assayed. Thermal inactivation method was used to kill the bacteria and preserve the bacterial surface proteins unchangeable. The concentrations of 0.01, 0.1, 0.5 and 1 mg/ml of inactivated bacteria were prepared to evaluate the effects of heat-inactivated bacterial solutions on MCF7 and HT-29 cell lines. MTT assay was used to measure the cell viability of cancer cells treated with different concentration of inactivated bacterial solutions.The MTT assay results after 48 hours showed that the heat-killed bacterial solutions were able to induce the proliferation of both cancer cell lines. In addition, the most cell viability in MCF-7 cell line was seen in samples treated with S. epidermidis, while in HT29 cells, the most one was seen in S. typhi treated samples. It was concluded that bacterial infections are cancer-deteriorating agents, and any species of bacteria is specific to certain cancerous tissue.

Schistosoma japonicum-Associated Colorectal Cancer: A Review

Schistosoma japonicum is a digenetic blood fluke that has been implicated in the carcinogenesis of several human malignancies, notably liver and colorectal cancer (CRC). Schistosoma japonicum-associated colorectal cancer (SACC) is a distinct subtype with biological behavior analogous to colitis-induced CRC. The clinicopathological characteristics of SACC include young age at diagnosis, predominance among males, a strong predilection for the sigmoid colon and rectum, multifocal distribution, frequent mucinous histology, and poor prognosis. In addition to chronic inflammation, immunomodulation, and schistosomal toxins, bacterial coinfection appears to play an important role in the carcinogenic process. The present review provides the most recent updates on epidemiology, pathobiology, and clinical and prognostic features pertaining to SACC.

Linking common non-coding RNAs of human lung cancer and M. tuberculosis

Lung cancer and pulmonary tuberculosis caused by Mycobacterium are two major causes of deaths worldwide. Tuberculosis linked lung cancer is known. However, the precise molecular mechanism of Mycobacterium associated increased risk of lung cancer is not understood. We report 45 common human miRNAs deregulated in both pulmonary tuberculosis and lung cancer. We show that sRNA_1096 and sRNA_1414 from M. tuberculosis have sequence homology with human mir-21. Hence, the potential role of these three small non-coding RNAs in rifampicin resistance in pulmonary tuberculosis is implied. Further, the linking of sRNA_1096 and sRNA_1414 from M. tuberculosis with the host lung tumorigenesis is inferred. Nonetheless, further analysis and validation is required to associate these three non-coding RNAs with Mycobacterium associated increased risk of lung cancer.

Gallbladder cancer: review of a rare orphan gastrointestinal cancer with a focus on populations of New Mexico

Gallbladder cancer is a rare malignancy of the biliary tract with a poor prognosis, frequently presenting at an advanced stage. While rare in the United States overall, gallbladder cancer has an elevated incidence in geographically distinct locations of the globe including Chile, North India, Korea, Japan and the state of New Mexico in the United States. People with Native American ancestry have a much elevated incidence of gallbladder cancer compared to Hispanic and non-Hispanic white populations of New Mexico. Gallbladder cancer is also one of the few bi-gendered cancers with an elevated female incidence compared to men. Similar to other gastrointestinal cancers, gallbladder cancer etiology is likely multi-factorial involving a combination of genomic, immunological, and environmental factors. Understanding the interplay of these unique epidemiological factors is crucial in improving the prevention, early detection, and treatment of this lethal disease. Previous studies have failed to identify a distinct genomic mutational profile in gallbladder cancers, however, work to identify promising clinically actionable targets is this form of cancer is ongoing. Examples include, interest in the HER2/Neu signaling pathway and the recognition that chronic inflammation plays a crucial role in gallbladder cancer pathogenesis. In this review, we provide a comprehensive overview of gallbladder cancer epidemiology, risk factors, pathogenesis, and treatment with a specific focus on the rural and Native American populations of New Mexico. We conclude this review by discussing future research directions with the goal of improving clinical outcomes for patients of this lethal malignancy.

Biofilm Producing Salmonella Typhi: Chronic Colonization and Development of Gallbladder Cancer

Salmonella enterica subspecies enterica serovar Typhi is the aetiological agent of typhoid or enteric fever. In a subset of individuals, S. Typhi colonizes the gallbladder causing an asymptomatic chronic infection. Nonetheless, these asymptomatic carriers provide a reservoir for further spreading of the disease. Epidemiological studies performed in regions where S. Typhi is endemic, revealed that the majority of chronically infected carriers also harbour gallstones, which in turn, have been indicated as a primary predisposing factor for the onset of gallbladder cancer (GC). It is now well recognised, that S. Typhi produces a typhoid toxin with a carcinogenic potential, that induces DNA damage and cell cycle alterations in intoxicated cells. In addition, biofilm production by S. Typhi may represent a key factor for the promotion of a persistent infection in the gallbladder, thus sustaining a chronic local inflammatory response and exposing the epithelium to repeated damage caused by carcinogenic toxins. This review aims to highlight the putative connection between the chronic colonization by highly pathogenic strains of S. Typhi capable of combining biofilm and toxin production and the onset of GC. Considering the high risk of GC associated with the asymptomatic carrier status, the rapid identification and profiling of biofilm production by S. Typhi strains would be key for effective therapeutic management and cancer prevention.

Gallbladder cancer epidemiology, pathogenesis and molecular genetics: Recent update

Gallbladder cancer is a malignancy of biliary tract which is infrequent in developed countries but common in some specific geographical regions of developing countries. Late diagnosis and deprived prognosis are major problems for treatment of gallbladder carcinoma. The dramatic associations of this orphan cancer with various genetic and environmental factors are responsible for its poorly defined pathogenesis. An understanding to the relationship between epidemiology, molecular genetics and pathogenesis of gallbladder cancer can add new insights to its undetermined pathophysiology. Present review article provides a recent update regarding epidemiology, pathogenesis, and molecular genetics of gallbladder cancer. We systematically reviewed published literature on gallbladder cancer from online search engine PubMed (http://www.ncbi.nlm.nih.gov/pubmed). Various keywords used for retrieval of articles were Gallbladder, cancer Epidemiology, molecular genetics and bullion operators like AND, OR, NOT. Cross references were manually searched from various online search engines (http://www.ncbi.nlm.nih.gov/pubmed,https://scholar.google.co.in/, http://www.medline.com/home.jsp). Most of the articles published from 1982 to 2015 in peer reviewed journals have been included in this review.

MICROBIOLOGICAL ANALYSIS OF BILE IN PATIENTS WITH BENIGN AND MALIGNANT BILIOPANCREATIC DISEASES AND ITS CONSEQUENCES

BACKGROUND

Bactibilia has several consequences to human health.

OBJETIVE

Assessing the bile microbiology of patients with biliopancreatic diseases in order to identify bacteria and their possible infectious complications.

METHODS

Retrospective study of 30 bile culture samples from patients with benign and malignant biliopancreatic diseases. The samples were assessed to set the bile microbiological flora and to search for its possible link with comorbidity, carcinogenesis and postoperative infectious complications.

RESULTS

Thirty bile samples from patients at mean age ≈57.7 years, mostly female (n=18), were assessed. Bactibilia was found in 12 cases, mostly in patients with benign diseases (n=8), older than 50 years (n=23) and female (n=10). Adenocarcinoma of the duodenal papilla (n=9) and cholelithiasis (n=8) were the most common diseases. Escherichia coli (n=5) and Klebsiella sp (n=3) were predominantly found in patients with benign diseases; and Klebsiella sp (n=2) and Streptococcus sp (n=2) were prevalent in cancer patients. There were postoperative infectious complications in seven cases, five of them in bactibilia-associated patients (P=0.084).

CONCLUSION

Bactibilia was found in 12 samples and Escherichia coli and Klebsiella sp were most often identified in patients with benign diseases, as well as Streptococcus sp and Klebsiella sp in cancer patients. There was a trend of higher postoperative infectious complication incidence in patients with bactibilia.

Salmonella enterica serovar Typhi and gallbladder cancer: a case-control study and meta-analysis

In Chile, where gallbladder cancer (GBC) rates are high and typhoid fever was endemic until the 1990s, we evaluated the association between Salmonella enterica serovar Typhi (S. Typhi) antibodies and GBC. We tested 39 GBC cases, 40 gallstone controls, and 39 population-based controls for S. Typhi Vi antibodies and performed culture and quantitative polymerase chain reaction for the subset with bile, gallstone, tissue, and stool samples available. We calculated gender and education-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the association with GBC. We also conducted a meta-analysis of >1000 GBC cases by combining our results with previous studies. GBC cases were more likely to have high Vi antibody titer levels than combined controls (OR: 4.0, 95% CI: 0.9-18.3), although S. Typhi was not recovered from bile, gallstone, tissue, or stool samples. In our meta-analysis, the summary relative risk was 4.6 (95% CI: 3.1-6.8, Pheterogeneity =0.6) for anti-Vi and 5.0 (95% CI: 2.7-9.3, Pheterogeneity  = 0.2) for bile or stool culture. Our results are consistent with the meta-analysis. Despite differences in study methods (e.g., S. Typhi detection assay), most studies found a positive association between S. Typhi and GBC. However, the mechanism underlying this association requires further investigation.

Infection and cancer in multicellular organisms

Evolutionary considerations suggest that oncogenic infections should be pervasive among animal species. Infection-associated cancers are well documented in humans and domestic animals, less commonly reported in undomesticated captive animals, and rarely documented in nature. In this paper, we review the literature associating infectious agents with cancer to evaluate the reasons for this pattern. Non-malignant infectious neoplasms occur pervasively in multicellular life, but oncogenic progression to malignancy is often uncertain. Evidence from humans and domestic animals shows that non-malignant infectious neoplasms can develop into cancer, although generally with low frequency. Malignant neoplasms could be difficult to find in nature because of a low frequency of oncogenic transformation, short survival after malignancy and reduced survival prior to malignancy. Moreover, the evaluation of malignancy can be ambiguous in nature, because criteria for malignancy may be difficult to apply consistently across species. The information available in the literature therefore does not allow for a definitive assessment of the pervasiveness of infectious cancers in nature, but the presence of infectious neoplasias and knowledge about the progression of benign neoplasias to cancer is consistent with a widespread but largely undetected occurrence.

Microbial influences on hormesis, oncogenesis, and therapy: A review of the literature

Utilization of environmental stimuli for growth is the main factor contributing to the evolution of prokaryotes and eukaryotes, independently and mutualistically. Epigenetics describes an organism's ability to vary expression of certain genes based on their environmental stimuli. The diverse degree of dose-dependent responses based on their variances in expressed genetic profiles makes it difficult to ascertain whether hormesis or oncogenesis has or is occurring. In the medical field this is shown where survival curves used in determining radiotherapeutic doses have substantial uncertainties, some as large as 50% (Barendsen, 1990). Many in-vitro radiobiological studies have been limited by not taking into consideration the innate presence of microbes in biological systems, which have either grown symbiotically or pathogenically. Present in-vitro studies neglect to take into consideration the varied responses that commensal and opportunistic pathogens will have when exposed to the same stimuli and how such responses could act as stimuli for their macro/microenvironment. As a result many theories such as radiation carcinogenesis explain microscopic events but fail to describe macroscopic events (Cohen, 1995). As such, this review shows how microorganisms have the ability to perturb risks of cancer and enhance hormesis after irradiation. It will also look at bacterial significance in the microenvironment of the tumor before and during treatment. In addition, bacterial systemic communication after irradiation and the host's immune responses to infection could explain many of the phenomena associated with bystander effects. Therefore, the present literature review considers the paradigms of hormesis and oncogenesis in order to find a rationale that ties them all together. This relationship was thus characterized to be the microbiome.

Medical conditions, family history of cancer, and the risk of biliary tract cancers

BACKGROUND

Scanty data exist on the role of personal medical conditions, except for gallstones, and family history of cancer on the risk of biliary tract cancers (BTC).

METHODS

We analyzed this issue using data from two Italian case-control studies, including 159 cases of BTC and 795 matched hospital controls. Odds ratios (ORs) of BTC and corresponding 95% confidence intervals (CIs) were estimated using multiple logistic regression models.

RESULTS

Gallstones were associated with a 2-fold excess risk of BTC (95% CI 1.24-3.45). No significant associations were observed with other conditions investigated, including diabetes (OR 1.15, 95% CI 0.63-2.11), hypertension (OR 0.65, 95% CI 0.39-1.11), hyperlipidemia (OR 0.61, 95% CI 0.31-1.21), allergy (OR 0.64, 95% CI 0.29-1.40), gastroduodenal ulcer (OR 0.52, 95% CI 0.24-1.12), hepatitis (OR 2.02, 95% CI 0.35-11.67), benign thyroid diseases (OR 1.16, 95% CI 0.56-2.40), hysterectomy (OR 1.19, 95% CI 0.53-2.68), unilateral oophorectomy (OR 1.75, 95% CI 0.44-6.93), and bilateral oophorectomy (OR 2.48, 95% CI 0.79-7.82). We found an excess risk of BTC in relation to family history of any cancer (OR 1.52, 95% CI 1.03-2.24) and family history of gallbladder cancer (OR 3.83, 95% CI 0.59-24.75).

CONCLUSIONS

The present study confirms a strong association between BTC and history of gallstones, and provides further evidence of a positive association with family history of cancer.

Development of broad-spectrum antibiofilm drugs: strategies and challenges

ABSTRACT 

The severity of many chronic bacterial infections is mainly due to the biofilm mode of life adapted by pathogenic bacteria. The bacteria in biofilm-stage exhibit high resistance to host immune responses and antimicrobials, which complicates the treatment process and results in life threatening conditions. Most of the chronic infections are polymicrobial in nature. In order to combat the polymicrobial biofilm infections and to increase the efficiency of antimicrobials, there is an urgent need for broad-spectrum antibiofilm drugs. This review discusses the clinical needs and current status of broad-spectrum antibiofilm drugs with special emphasis on prospective strategies and hurdles in the process of new drug discovery.

Gallbladder cancer: Clinical and pathological approach

Gallbladder cancer (GBC) shows a marked geographical variation in its incidence. Middle-aged and elderly women are more commonly affected. Risk factors for its development include the presence of gallstones, chronic infection and pancreaticobiliary maljunction. Controversy remains in regard to the theory of carcinogenesis from adenomyomatosis, porcelain gallbladder and adenoma of the gallbladder. The surgical strategy and prognosis after surgery for GBC differ strikingly according to T-stage. Discrimination of favorable cases, particularly T2 or T3 lesions, is useful for the selection of surgical strategies for individual patients. Although many candidate factors predicting disease progression, such as depth of subserosal invasion, horizontal tumor spread, tumor budding, dedifferentiation, Ki-67 labeling index, p53 nuclear expression, CD8+ tumor-infiltrating lymphocytes, mitotic counts, Laminin-5-gamma-2 chain, hypoxia-inducible factor-1a, cyclooxygenase-2 and the Hedgehog signaling pathway have been investigated, useful prognostic makers or factors have not been established. As GBC is often discovered incidentally after routine cholecystectomy and accurate preoperative diagnosis is difficult, close mutual cooperation between surgeons and pathologists is essential for developing a rational surgical strategy for GBC.

Streptococcus bovis infection and colorectal neoplasia: a meta-analysis

AIM

A meta-analysis was conducted to determine the risk associated with Streptococcus bovis infection and the occurrence of colorectal neoplasia (CRN). The level of risk remains unknown.

METHOD

We conducted a search of MEDLINE, PubMed and EMBASE up to January 2014. We used a random-effects model to analyse the data.

RESULTS

We identified 48 studies concerning three main topics: S. bovis septicaemia, S. bovis endocarditis and S. bovis faecal carriage. The total sample sizes were 1729, 807 and 1145, respectively; the 48 studies included 9 case-control studies and 39 case series. Overall, the presence of S. bovis infection was found to be significantly associated with the presence of CRN. Streptococcus bovis endocarditis showed the strongest association in analyses of case-control studies and case series (OR 14.54, 95% CI 5.66-37.35, test for heterogeneity I2 = 43.53; event rate of 0.53, 95% CI 0.45-0.61, test for heterogeneity I2 = 53.50). Similarly, S. bovis septicaemia was also associated with a high level of concurrence with CRN (OR 7.48, 95% CI 3.10-18.06, test for heterogeneity I(2) = 43.32; event rate 0.49, 95% CI 0.42-0.56, test for heterogeneity I2 = 69.97). Patients with CRN were found to have a higher incidence of S. bovis in faeces upon stool culture (OR 2.52, 95% CI 1.14-5.58, test for heterogeneity I2 = 69.17).

CONCLUSION

The meta-analysis showed a statistically significant association between the presence of S. bovis endocarditis or S. bovis septicaemia and CRN. Furthermore, there is a statistically significant increase in likelihood of finding S. bovis in the stool of individuals with CRN.

Joint infectious causation of human cancers

Joint infectious causation of cancer has been accepted in a few well-studied instances, including Burkitt's lymphoma and liver cancer. In general, evidence for the involvement of parasitic agents in oncogenesis has expanded, and recent advances in the application of molecular techniques have revealed specific mechanisms by which host cells are transformed. Many parasites evolve to circumvent immune-mediated detection and destruction and to control critical aspects of host cell reproduction and survival: cell proliferation, apoptosis, adhesion, and immortalization. The host has evolved tight regulation of these cellular processes-the control of each represents a barrier to cancer. These barriers need to be compromised for oncogenesis to occur. The abrogation of a barrier is therefore referred to as an essential cause of cancer. Alternatively, some aspects of cellular regulation restrain but do not block oncogenesis. Relaxation of a restraint is therefore referred to as an exacerbating cause of cancer. In this chapter, we explore past and current evidence for joint infectious causation of cancer in the context of essential and exacerbating causes. We stress that discovery of joint infectious causation may provide great improvements in controlling cancer, particularly through the identification of many additional nonhuman targets for synergistic interventions for prevention and treatment.

Partial associations of dietary iron, smoking and intestinal bacteria with colorectal cancer risk

Smoking and high red meat intake have been associated with colorectal cancer (CRC) risk. Increased iron exposure may be a common factor, favoring the colonization of certain bacterial pathogens that preferentially grow in an iron-rich luminal environment. We analyzed the data from a population-based case-control study of CRC and measured antibody levels against flagelin of Salmonella (FliC), one of the irontrophic bacteria, in 2 independent blood collections. The risk of CRC synergistically increased by combined exposures to heme iron intake and pack-yr (PY) of cigarette smoking (P value for the interaction = 0.039 on the continuous scale). There was a marginally significant interaction between heme iron intake and PY in increasing FliC antibody in the U.S. control subjects (P = 0.055), although no iron or smoking data were available for Dutch samples. Furthermore, FliC antibody levels were significantly higher in patients with colorectal polyps and cancer than in controls in both Dutch (3.93 vs. 2.23) (P = 0.014) and U.S. samples (6.65 vs. 4.37) (P < 0.001). Potential roles of iron from cigarette smoking and dietary heme in CRC through altering irontrophic luminal bacterial population may warrant further investigation.

Metaplastic changes in chronic cholecystitis: implications for early diagnosis and surgical intervention to prevent the gallbladder metaplasia-dysplasia-carcinoma sequence

Background

Metaplastic features of the gallbladder epithelium are considered to be the precursors of gallbladder cancer. Considering the possible role of chronic inflammatory changes in the development of these lesions and the rationale for performing an early prophylactic cholecystectomy, we performed a retrospective study to assess the prevalence of gallbladder metaplasia in patients who underwent cholecystectomy due to underlying cholelithiasis.

Methods

We reviewed the routine histopathology reports of 86 patients with chronic cholecystitis, who underwent elective cholecystectomy, to assess the prevalence of gallbladder metaplasia in the course of chronic cholecystitis. We further attempted to evaluate the existence of any correlations between the presence of the gallbladder metaplasia and the type of lithiasis, as well as the gallbladder wall thickness.

Results

The overall prevalence of metaplastic features in the resected specimens was 25.6%. Dysplastic changes were more frequent in gallbladder specimens with concurrent metaplasia. Moreover, in presence of metaplastic changes, we observed an increase of the average gallbladder wall thickness. Finally, metaplastic and dysplastic changes were associated with the presence of micro-lithiasis rather than macro-lithiasis.

Conclusions

Gallbladder metaplastic changes appear to be more frequent in cases of micro-lithiasis and seem to be associated with a chronic thickening of the gallbladder wall. Taking into account the usually sub-clinical course of this group of patients, when compared to patients with macro-lithiasis, further studies are needed to evaluate a possible role of prophylactic cholecystectomy in this population to prevent the long term evolution of these early changes to cancerous lesions.

Streptococcus infantarius and carcinogenesis: a new chapter in colorectal pathology

As mirrored by several topics throughout history, the causal link between infectious diseases and cancer was initially viewed with disbelief and subsequently forgotten, only to be rediscovered decades later, when it started flourishing into a vibrant multidisciplinary field . Just a few years ago, it was estimated that over 20% of all cancers are causally linked to infectious diseases, most frequently caused by bacteria, viruses, and parasites .

Modern perspectives on factors predisposing to the development of gallbladder cancer

BACKGROUND

Gallbladder cancer (GBC) is a rare malignancy, yet certain groups are at higher risk. Knowledge of predisposing factors may facilitate earlier diagnosis by enabling targeted investigations into otherwise non-specific presenting signs and symptoms. Detecting GBC in its initial stages offers patients their best chance of cure.

METHODS

PubMed was searched for recent articles (2008-2012) on the topic of risk factors for GBC. Of 1490 initial entries, 32 manuscripts reporting on risk factors for GBC were included in this review.

RESULTS

New molecular perspectives on cholesterol cycling, hormonal factors and bacterial infection provide fresh insights into the established risk factors of gallstones, female gender and geographic locality. The significance of polyps in predisposing to GBC is probably overstated given the known dysplasia-carcinoma and adenoma-carcinoma sequences active in this disease. Bacteria such as Salmonella species may contribute to regional variations in disease prevalence and might represent powerful targets of therapy to reduce incidences in high-risk areas. Traditional risk factors such as porcelain gallbladder, Mirizzi's syndrome and bile reflux remain important as predisposing factors.

CONCLUSIONS

Subcentimetre gallbladder polyps rarely become cancerous. Because gallbladder wall thickening is often the first sign of malignancy, all gallbladder imaging should be scrutinized carefully for this feature.

Bacterial oncogenesis in the colon

The human colon plays host to a diverse and metabolically complex community of microorganisms. While the colonic microbiome has been suggested to contribute to the development of colorectal cancer (CRC), a definitive link has not been made. The role in which the colon microflora could contribute to the initiation and/or progression of CRC is explored in this review. Potential mechanisms of bacterial oncogenesis are presented, along with lines of evidence derived from animal models of microbially induced CRC. Particular focus is given to the oncogenic capabilities of enterotoxigenic Bacteroides fragilis. Recent progress in defining the microbiome of CRC in the human population is evaluated, and the future challenges of linking specific etiologic agents to CRC are emphasized.

Chronic inflammation and gallbladder cancer

Gallbladder cancer (GBC) is the most common biliary tract malignancy with an extremely poor prognosis. Epidemiological data have demonstrated that chronic inflammation resulting from infection of gallbladder or gallstones predispose individuals to GBC. Recent studies have begun to elucidate molecular mechanisms underlying the development of GBC in the setting of chronic inflammation. It is possible that persistently local inflammatory reactions may contribute to the development and progression of GBC through inducing genetic alterations, and subsequent promoting survival and proliferation of mutated sells, inhibiting apoptosis, stimulating angiogenesis and metastasis. This article reviews the current understanding of the involvement of chronic inflammation in gallbladder tumorigenesis.

Endocarditis and risk of cancer: a Danish nationwide cohort study

BACKGROUND

Endocarditis may be a marker for bacteremia-associated occult cancer. Intensive antibiotic treatment in endocarditis is suggested to reduce long-term cancer risk. We examined these hypotheses in a nationwide cohort study.

METHODS

Endocarditis patients and cancer cases were identified from the Danish National Registry of Patients and the Danish Cancer Registry during 1978-2008. We compared the incidences of various cancers among study subjects to expected incidences based on national age-, sex-, and site-specific rates.

RESULTS

We observed 997 cancers among 8445 endocarditis patients (median follow-up of 3.5 years), reflecting an increased standardized incidence rate (SIR) of 1.61 (95% confidence interval [CI], 1.51-1.71). Cancer risk was highly elevated during the first 3 months of follow-up (SIR=8.03; 95% CI, 6.92-9.26), partly due to a 15- to 30-fold increased risk of hematological or liver cancers. Between 3-month and 5-year follow-ups, cancer incidence remained 1.5-fold higher than expected, including 2- and 4-fold increased SIRs for colorectal and liver cancers, respectively. Beyond 5 years of observation, the overall cancer SIR was 1.21 (95% CI, 1.10-1.34). Long-term associations were weak for several cancers hypothesized to be associated with antibiotic use, including prostate, gastric, and breast cancer.

CONCLUSION

Endocarditis is a substantial clinical marker for presence of occult cancer. We found no evidence of decreased long-term cancer risk after antibiotic treatment for endocarditis.

Gallbladder cancer: past, present and an uncertain future

Although gallbladder cancer (GBC) is the most common malignancy of the biliary tract, its relatively low incidence and confounding symptomatology result in advanced disease at the time presentation, contributing to the poor prognosis and decreased survival associated with this disease. It is therefore increasingly important to understand its pathogenesis and risk factors to allow for the earliest possible diagnosis. To date, gallbladder cancer is poorly understood compared to other malignancies, and is still most commonly discovered incidentally after cholecystectomy. Moreover, while much is known about biliary neoplasms as a whole, understanding the clinical and molecular nuances of GBC as a separate disease process will prove a cornerstone in the development of early intervention, potential screening and overall more effective treatment strategies. The present work reviews the most current understanding of the pathogenesis, diagnosis, staging and natural history of GBC, with additional focus on surgical treatment. Further, review of current adjuvant therapies for unresectable and advanced disease as well as prognostic factors provide fertile ground for the development of future studies which will hopefully improve treatment outcomes and affect overall survival for this highly morbid, poorly understood malignancy.

Bacterial isolates from the urine of cattle affected by urothelial tumors of the urinary bladder

Microbiological investigations were performed on urine samples from 108 cows affected by urothelial tumors of the urinary bladder. Bacteria, frequently of mixed population, were isolated from 100 animals. Gram-positive bacteria prevailed, with Staphylococcus spp. and Bacillus spp. being the most common. Escherichia coli and Acinetobacter spp. were the most frequently recovered Gram-negative bacteria. E5 oncoprotein was detected in 86 of the 108 urothelial tumors under study. In the majority of cases, bacterial agents and BPV-2 E5 were simultaneously detected. A marked down-regulation of Tamm-Horsfall protein was also observed in the examined cases. In addition, the p65 subunit of the nuclear factor-κB (NF-κB) transcription factor appeared to be overexpressed. In all cases, a mild to severe chronic inflammation was evident in the stroma of urinary bladder tumors. Bacterial components may play a role in the activation of the NF-κB and might cause chronic inflammation resulting in an impaired ability to clear BPV-2 infection, thus cooperating with the virus in cancer development. As in man, therefore, bacteria could play both a direct and an indirect role in bovine bladder carcinogenesis.

Rho/ROCK-dependent inhibition of 3T3-L1 adipogenesis by G-protein-deamidating dermonecrotic toxins: differential regulation of Notch1, Pref1/Dlk1, and β-catenin signaling

The dermonecrotic toxins from Pasteurella multocida (PMT), Bordetella (DNT), Escherichia coli (CNF1-3), and Yersinia (CNFY) modulate their G-protein targets through deamidation and/or transglutamination of an active site Gln residue, which results in activation of the G protein and its cognate downstream signaling pathways. Whereas DNT and the CNFs act on small Rho GTPases, PMT acts on the α subunit of heterotrimeric G_q, G_i, and G_12/13 proteins. We previously demonstrated that PMT potently blocks adipogenesis and adipocyte differentiation in a calcineurin-independent manner through downregulation of Notch1 and stabilization of β-catenin and Pref1/Dlk1, key proteins in signaling pathways strongly linked to cell fate decisions, including fat and bone development. Here, we report that similar to PMT, DNT, and CNF1 completely block adipogenesis and adipocyte differentiation by preventing upregulation of adipocyte markers, PPARγ and C/EBPα, while stabilizing the expression of Pref1/Dlk1 and β-catenin. We show that the Rho/ROCK inhibitor Y-27632 prevented or reversed these toxin-mediated effects, strongly supporting a role for Rho/ROCK signaling in dermonecrotic toxin-mediated inhibition of adipogenesis and adipocyte differentiation. Toxin treatment was also accompanied by downregulation of Notch1 expression, although this inhibition was independent of Rho/ROCK signaling. We further show that PMT-mediated downregulation of Notch1 expression occurs primarily through G_12/13 signaling. Our results reveal new details of the pathways involved in dermonecrotic toxin action on adipocyte differentiation, and the role of Rho/ROCK signaling in mediating toxin effects on Wnt/β-catenin and Notch1 signaling, and in particular the role of G_q and G_12/13 in mediating PMT effects on Rho/ROCK and Notch1 signaling.