Parasite Infection, Carcinogenesis and Human Malignancy

The landscape of etiological patterns of hepatocellular carcinoma and intrahepatic cholangiocarcinoma in Thailand

Thailand is among countries with the highest global incidence and mortality rates of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). While viral hepatitis and liver fluke infections have been associated with HCC and iCCA, respectively, other environmental risk factors, overall risk factor commonality and combinatorial roles, and effects on survival have not been systematically examined. We conducted a TIGER-LC consortium-based population study covering all high-incidence areas of both malignancies across Thailand: 837 HCC, 1474 iCCA, and 1112 controls (2011-2019) were comprehensively queried on lifelong environmental exposures, lifestyle, and medical history. Multivariate logistic regression and Cox proportional hazards analyses were used to evaluate risk factors and associated survival patterns. Our models identified shared risk factors between HCC and iCCA, such as viral hepatitis infection, liver fluke infection, and diabetes, including novel and shared associations of agricultural pesticide exposure (OR range of 1.50; 95% CI: 1.06-2.11 to 2.91; 95% CI: 1.82-4.63) along with vulnerable sources of drinking water. Most patients had multiple risk factors, magnifying their risk considerably. Patients with lower risk levels had better survival in both HCC (HR 0.78; 95% CI: 0.64-0.96) and iCCA (HR 0.84; 95% CI: 0.70-0.99). Risk factor co-exposures and their common associations with HCC and iCCA in Thailand emphasize the importance for future prevention and control measures, especially in its large agricultural sector. The observed mortality patterns suggest ways to stratify patients for anticipated survivorship and develop plans to support medical care of longer-term survivors, including behavioral changes to reduce exposures.

Detection of trichomonads in patients with lung cancer and transcription analysis on the response of human pulmonary epithelial cells to Trichomonas tenax invasion

INTRODUCTION

Lung cancer is one of the most prevalent malignancies worldwide. Substantial research has illuminated the intricate interplay between microorganisms and human health, revealing their role in disease regulation. Trichomonads is a flagellated protozoan in the human cavity and have been previously identified as a pathogen associated with pneumonia, contributing to tissue chronic inflammation and carcinogenesis.

METHODS

Nested polymerase chain reaction methods were employed to scrutinize the prevalence of trichomonads in the bronchovesicular fluid of patients diagnosed with lung cancer. Subsequently, the influence of Trichomonas tenax invasion on lung cancer cells was elucidated through proliferation assays, migration assays, and transcription analysis.

RESULTS

Bronchoalveolar fluid samples from lung cancer patients yielded positive nested PCR results for eight out of twenty-seven samples. Seven of these samples were identified as Trichomonas tenax, while one was identified as Tetratrichomonas spp. Our findings revealed a significant upregulation of pathways associated with carcinogenesis, including cellular proliferation, migration, and drug resistance, in response to T. tenax invasion.

CONCLUSIONS

This study underscores the importance of recognizing the presence of trichomonads and the influence of T. tenax invasion on host responses to respiratory diseases. The identified pathways implicated in cancer development may pave the way for developing targeted treatment strategies for pulmonary diseases. These findings hold promise for informing and improving the precision of therapeutic interventions in the context of pulmonary ailments.

The Parasitism and Tumors Carcinogenesis: A Review Subject

BACKGROUND

Multi-factorial reasons are an induction to cause cancer. Different infections and infestations with viruses, bacteria, and parasites have been detected for many years to be related to human carcinogenesis.

PURPOSE

The study aimed to review all ideas of tumor carcinogenesis and its associations with parasitic infections and infestations.

METHODS

We reviewed several articles (published and imprinted) by selecting, extracting, and synthesizing data about the relationship between cancers and parasites.

RESULTS

Several helminths infections as schistosomiasis, are highly carcinogenic agents for bladder cancer, whereas trypanosomiasis has a bi-model role in cancer development. Leishmaniasis may be a cause of hepatocarcinoma, skin cancer, and lymphomas. In addition, malaria appears to be causative in the carcinogenesis of some cancers; as Burkitt lymphoma. Also, data from previous studies suggested that Strongyloides stercoralis may be a relevant co-factor in lymphomas.

CONCLUSION

There are different mechanisms of parasitic infection to be enhancing in carcinogenesis of cancer in human.

Trypanosoma cruzi, Chagas disease and cancer: putting together the pieces of a complex puzzle

Considering the extensive and widespread impact on individuals, cancer can presently be categorized as a pandemic. In many instances, the development of tumors has been linked to endemic microbe infections. Among parasitic infections, Trypanosoma cruzi stands out as one of the most extensively discussed protozoans in the literature that explores the association between diseases of parasite origin and cancer. However, the effective association remains an unsolved paradox. Both the parasite, along with protozoan-derived molecules, and the associated antiparasitic immune response can induce alterations in various host cell pathways, leading to modifications in cell cycle, metabolism, glycosylation, DNA mutations, or changes in neuronal signaling. Furthermore, the presence of the parasite can trigger cell death or a senescent phenotype and modulate the immune system, the metastatic cascade, and the formation of new blood vessels. The interaction among the parasite (and its molecules), the host, and cancer undoubtedly encompasses various mechanisms that operate differentially depending on the context. Remarkably, contrary to expectations, the evidence tilts the balance toward inhibiting tumor growth or resisting tumor development. This effect is primarily observed in malignant cells, rather than normal cells, indicating a selective or specific component. Nevertheless, nonspecific bystander mechanisms, such as T. cruzi's adjuvancy or the presence of proinflammatory cytokines, may also play a significant role in this phenomenon. This work aims to elucidate this complex scenario by synthesizing the main findings presented in the literature and by proposing new questions and answers, thereby adding pieces to this challenging puzzle.

From the discovery of helminths to the discovery of their carcinogenic potential

Cancer involves a major aberration in the normal behaviour of cells, making them divide continuously, which interferes with the normal physiology of the body. The link between helminths and their cancer-inducing potential has been proposed in the last century. The exact pathway is still not clear but chronic inflammation in response to the deposited eggs, immune response against soluble egg antigens, and co-infection with a third party (a bacteria, a virus, or infection leading to a change in microbiome) seems to be the reasons for cancer induction. This review looks into the historical outlook on helminths along with their epidemiology, morphology, and life cycle. It then focuses on providing correlations between helminth infection and molecular mechanism of carcinogenesis by elaborating upon epidemiological, clinical, and surgical studies. While the cancer-inducing potential has been convincingly established only for a few helminths and studies point out towards possible cancer-inducing ability of the rest of the helminths elucidated in this work, however, more insights into the immunobiology of helminths as well as infected patients are required to conclusively comment upon this ability of the latter.

Schistosoma japonicum Associated Colorectal Cancer and Its Management

BACKGROUND

An association between Schistosoma japonicum and colorectal cancer in humans has been known since a long time; however, this association remains understudied and lacks comprehensive experimentation support.

OBJECTIVE

Various epidemiological and pathological studies have established the role of chronic inflammation as a major factor behind the induction of colorectal cancer. The aim of this review is to present the current knowledge on the association of Schistosoma japonicum with colorectal cancer.

RESULT

Mechanisms which lead to induction and progression of colorectal cancer are highlighted along with diagnosis and treatment for the same. Further, various methodologies, including mass drug administration, use of new drugs and vaccines, role of apoptosis, and histone-modifying enzymes, have been described which can either prevent the schistosomal infection itself or can check it from reaching an advanced stage.

CONCLUSIONS

Epidemiological, clinical, pathological and surgical studies suggest that Schistosoma japonicum is responsible for induction of colorectal cancer. However, thorough clinical studies are required to support and globally accept this notion. Further, methodologies highlighted in this work can be employed in order to take care of schistosomal infection or address the cancer induction and progression.

Curcumin-loaded nanocomplexes alleviate the progression of fluke-related cholangiocarcinoma in hamsters

Background

Curcumin-loaded nanocomplexes (CNCs) previously demonstrated lower toxicity and extended release better than is the case for free curcumin. Here, we evaluated the efficacy of CNCs against opisthorchiasis-associated cholangiocarcinoma (CCA) in hamsters.

Method

Dose optimization (dose and frequency) was performed over a 1-month period using hamsters, a model that is widely used for study of opisthorchiasis-associated cholangiocarcinoma. In the main experimental study, CCA was induced by a combination of fluke, Opisthorchis viverrini (OV), infection and N-nitrosodimethylamine (NDMA) treatment. Either blank (empty) nanocomplexes (BNCs) or different concentrations of CNCs (equivalent to 10 and 20 mg cur/kg bw) were given to hamsters thrice a week for 5 months. The histopathological changes, biochemical parameters, and the expression of inflammatory/oncogenic transcription factors were investigated. In addition, the role of CNCs in attenuating CCA genesis, as seen in an animal model, was also confirmed in vitro using CCA cell lines.

Results

The optimization study revealed that treatment with CNCs at a dose equivalent to 10 mg cur/kg bw, thrice a week for 1 month, led to a greater reduction of inflammation and liver injury induced in hamsters by OV + NDMA than did treatments at other dose rates. Oral administration with CNCs (10 mg cur/kg bw), thrice a week for 5 months, significantly increased survival rate, reduced CCA incidence, extent of tumor development, cholangitis, bile duct injury and cholangiofibroma. In addition, this treatment decreased serum ALP and ALT activities and suppressed expression of NF-κB, FOXM1, HMGB1, PCNA and formation of 8-nitroguanine. Treatment of CCA cell lines with CNCs also reduced cell proliferation and colony formation, similar to those treated with NF-κB and/or FOXM1 inhibitors.

Conclusion

CNCs (10 mg cur/kg bw) attenuate the progression of fluke-related CCA in hamsters partly via a NF-κB and FOXM1-mediated pathway.

Conjoint analysis of clinical, imaging, and pathological features of schistosomiasis and colorectal cancer

This study aims to examine and compare clinical, radiological, and pathological data between colorectal cancer (CRC) patients with and without schistosomiasis and uncover distinctive CRC characteristics when accompanied by schistosomiasis. This retrospective study is based on data collected from 341 patients diagnosed with CRC post-surgery and pathology. Of these patients, 101 (Group A) were diagnosed with colorectal cancer co-occurring with schistosomiasis (CRC-S), while 240 patients (Group B) were diagnosed with colorectal cancer without concurrent schistosomiasis (CRC-NS). Both groups were compared and analyzed based on their clinical data, imaging-based TNM staging, lymph node metastasis, nerve invasion, vascular cancer thrombus, and histopathological differentiation. A Chi-squared test revealed a significant difference in gender distribution between the patients with CRC-S (Group A) and CRC-NS (Group B), with a p -value of 0.043 and χ2 = 4.115. Specifically, a higher incidence rate was observed among males in Group A. There was a difference in the overall distribution of TNM staging between the two groups (p = 0.034, χ2 = 6.764). After pairwise comparison, a statistically significant difference was observed in the T3 stage (p <0.05). The proportion of the T3 stage in Group A was significantly higher than that in Group B, indicating certain advantages. There was a difference in postoperative histopathological grading between the two groups (p = 0.005, χ2 = 10.626). After pairwise comparison, a statistically significant difference was observed between the well-differentiated adenocarcinoma and the moderately and poorly differentiated adenocarcinoma (p <0.05), with a higher proportion of welldifferentiated patients in Group A compared to Group B. There was no significant difference in age, lymph node metastasis, nerve invasion, and vascular invasion between the two groups of patients (p > 0.05). Among the 101 patients with CRC-S, 87 (86%) showed linear calcification on CT imaging. Patients with CRC-S are mainly male, with tumor staging mostly in the middle stage, high tumor differentiation, and low malignancy. CT imaging can help identify the presence of lumps and linear calcification indicative of schistosome deposits. MRI can early clarify TNM staging and determine the presence of lymph node metastasis and nerve and vascular invasion.

Presence of schistosome eggs in lymph node predict unfavorable prognosis in schistosomal colorectal cancer

OBJECTIVE

The purpose of this study was to investigate the prognostic significance of schistosome eggs' location in schistosomal colorectal cancer (SCRC).

METHODS

172 cases of SCRC were retrospectively analyzed. Patient clinicopathological parameters and survival rates were analyzed.

RESULTS

There were 102 males and 70 females, the median age was 71 years (range, 44-91). All patients were followed, and the median time was 50.1 months (range, 1.0-79.7). There were 87 patients with PS1 (presence site 1, eggs deposited in the mucosa) and 85 patients with PS2 (presence site 2, eggs deposited in the muscularis propria or throughout the full thickness of the intestinal wall), 159 patients presented with eggs in cutting edge and 83 patients presented with eggs in lymph node (LN). Hepatic schistosomiasis was found in 27.3% of patients by imaging modalities and correlated to patients with PS2 ( P < 0.001) and LNs' eggs ( P < 0.001). Survival analyses showed that in stage III SCRC, eggs' presence in LN associated with worse DFS ( P = 0.004) or marginally worse OS ( P = 0.056), patients with PS2 had shorter OS ( P = 0.044). Multivariate analyses revealed hepatic schistosomiasis was an independent prognostic factor for DFS and OS in stage III SCRC ( P = 0.001, 0.002, respectively). In adjusted multivariate analysis, eggs' presence in LN was an independent prognostic factor for DFS in stage III SCRC ( P = 0.006).

CONCLUSIONS

In stage III SCRC, eggs' presence in LN could predict poor prognosis and hepatic schistosomiasis was an independently unfavorable prognosis factor.

Clonorchis sinensis calcium-binding protein Cs16 causes acute hepatic injury possibly by reprogramming the metabolic pathway of bone marrow-derived monocytes

Introduction

Clonorchis sinensis infection results in various complications in the liver and biliary systems and is a neglected tropical disease in Eastern Asia. In this study, we report that C. sinensis calcium-binding protein Cs16 activates host immune cells and induces immunopathology in liver.

Methods

Immunohistochemistry was used to detect the localization of Cs16 in C. sinensis adult worms. ELISA was used to detect the serum levels of anti-Cs16 IgG antibody in infected humans and mice. Bile duct injection model was used to figure out the role of Cs16 in vivo. RT-qPCR and ELISA were used to detect the cytokine production from Cs16-treated BMMs in vitro. Seahorse assay was used to detect the metabolic pathway of Cs16-treated BMMs in vitro.

Result

Cs16 localizes in the tegument and gut of C. sinensis. Humans and mice with C. sinensis infection exhibited increased levels of anti-Cs16-specific antibody. Using the bile duct injection technique, we found that Cs16 induced obvious inflammation and hepatic necrosis in vivo. Cs16 treatment caused the upregulation of inflammatory cytokines in innate immune cells. Moreover, Cs16-treated monocytes relied more on the glycolytic metabolic pathway.

Discussion

Our findings suggest that Cs16 is a potential pathogenic factor derived from C. sinensis adult worm. By reprogramming the metabolic pathway of innate immune cells, Cs16 triggers pro-inflammatory responses in the liver, and therefore, Cs16 is a potential target for the prevention and treatment of clonorchiasis.

Cancerogenic parasites in veterinary medicine: a narrative literature review

Parasite infection is one of the many environmental factors that can significantly contribute to carcinogenesis and is already known to be associated with a variety of malignancies in both human and veterinary medicine. However, the actual number of cancerogenic parasites and their relationship to tumor development is far from being fully understood, especially in veterinary medicine. Thus, the aim of this review is to investigate parasite-related cancers in domestic and wild animals and their burden in veterinary oncology. Spontaneous neoplasia with ascertained or putative parasite etiology in domestic and wild animals will be reviewed, and the multifarious mechanisms of protozoan and metazoan cancer induction will be discussed.

A Diverse Virome Is Identified in Parasitic Flatworms of Domestic Animals in Xinjiang, China

Parasitic flatworms infect diverse vertebrates and are major threats to animal and even human health; however, little is known about the virome of these lower life forms. Using viral metagenomic sequencing, we characterized the virome of the parasitic flatworms collected from major domestic animals, including Dicrocoelium lanceatum and Taenia hydatigena, Echinococcus granulosus sensu stricto and Echinococcus multilocularis. Seven and three different viruses were discovered from D. lanceatum and T. hydatigena, respectively, and no viral sequences were found in adult tapeworms and protoscoleces of E. granulosus sensu stricto and E. multilocularis. Two out of the five parasitic flatworm species carry viruses, showing a host specificity of these viruses. These viruses belong to the Parvoviridae, Circoviridae, unclassified circular, Rep-encoding single-stranded (CRESS) DNA virus, Rhabdoviridae, Endornaviridae, and unclassified RNA viruses. The presence of multiple highly divergent RNA viruses, especially those that cluster with viruses found in marine animals, implies a deep evolutionary history of parasite-associated viruses. In addition, we found viruses with high identity to common pathogens in dogs, including canine circovirus and canine parvovirus 2. The presence of these viruses in the parasites implies that they may infect parasitic flatworms but does not completely exclude the possibility of contamination from host intestinal contents. Furthermore, we demonstrated that certain viruses, such as CRESS DNA virus may integrate into the genome of their host. Our results expand the knowledge of viral diversity in parasites of important domestic animals, highlighting the need for further investigations of their prevalence among other parasites of key animals. IMPORTANCE Characterizing the virome of parasites is important for unveiling the viral diversity, evolution, and ecology and will help to understand the "Russian doll" pattern among viruses, parasites, and host animals. Our data indicate that diverse viruses are present in specific parasitic flatworms, including viruses that may have an ancient evolutionary history and viruses currently circulating in parasite-infected host animals. These data also raise the question of whether parasitic flatworms acquire and/or carry some viruses that may have transmission potential to animals. In addition, through the study of virus-parasite-host interactions, including the influence of viral infection on the life cycle of the parasite, as well as its fitness and pathogenicity to the host, we could find new strategies to prevent and control parasitic diseases.

Onco-Pathogen Mediated Cancer Progression and Associated Signaling Pathways in Cancer Development

Infection with viruses, bacteria, and parasites are thought to be the underlying cause of about 8-17% of the world's cancer burden, i.e., approximately one in every five malignancies globally is caused by an infectious pathogen. Oncogenesis is thought to be aided by eleven major pathogens. It is crucial to identify microorganisms that potentially act as human carcinogens and to understand how exposure to such pathogens occur as well as the following carcinogenic pathways they induce. Gaining knowledge in this field will give important suggestions for effective pathogen-driven cancer care, control, and, ultimately, prevention. This review will mainly focus on the major onco-pathogens and the types of cancer caused by them. It will also discuss the major pathways which, when altered, lead to the progression of these cancers.

Cancer and Trypanosoma cruzi: Tumor induction or protection?

Trypanosoma cruzi causes Chagas disease, a neglected disease that can be divided, overall, into acute and chronic phases. Understanding the mechanisms underlying its progression is based on the parasite-host interactions occurring during the infection. Although the pathophysiology of the main symptomatic forms of Chagas disease has been the subject of several studies, little is known about their relationship with the development of different types of cancer. Therefore, knowledge regarding the molecular aspects of infection in the host, as well as the influence of the immune response in the parasite and the host, can help to understand the association between Chagas disease and tumor development. This review aims to summarize the main molecular mechanisms related to T. cruzi-dependent carcinogenic development and the mechanisms associated with tumor protection mediated by different parasite components.

Detection of unusual Cryptosporidium parvum subtype in patients with gastrointestinal cancer in Egypt

While the importance of cryptosporidiosis in immunocompromised persons is well known, the prevalence of Cryptosporidium spp. in cancer patients is not clear. The current study was designed to assess the occurrence and genetic characteristics of Cryptosporidium spp. in patients with gastrointestinal (GI) cancer in Egypt. Stool samples were collected from 100 patients with GI malignancies and 20 healthy individuals without any GI manifestations (control group). They were screened by microscopy and the immunochromatographic RIDA®QUICK Cryptosporidium kit. Subtyping of Cryptosporidium spp. was conducted by sequence analysis of the glycoprotein 60 (gp60) locus. Sociodemographic, environmental data and information on GI symptoms, cancer types, and clinical treatment were obtained via a questionnaire. By microscopy and RIDA®QUICK, only 7% (7/100) of GI cancer patients were positive for Cryptosporidium, compared with 40% (40/100) by gp60 nPCR. No positives were obtained from the control group. Male sex (P = 0.02) and younger age (P = 0.004) were major Cryptosporidium risk factors for infection. The occurrence of Cryptosporidium was also significantly more frequent (P = 0.003) in watery stool samples. Sequence analysis of the gp60 amplicons (~ 400 bp) identified a novel C. parvum subtype with nine TCA repeats and eleven ACATCA repeats. A formal subtype designation could not be made due to the short sequence length. More studies should be conducted to verify the common occurrence of this unusual C. parvum subtype and establish its genetic identity.

Clinical and Pathological Features of Hydroa Vacciniforme-Like Lymphoproliferative Disorder Along with Risk Factors Indicating Poor Prognosis

Purpose

To examine the clinical and pathological features, laboratory markers, therapeutic options and risk factors indicating poor prognosis of hydroa vacciniforme-like lymphoproliferative disorder (HVLPD).

Patients and Methods

Seven patients with HVLPD had their clinical and pathological data collected. Immunohistochemical staining, Epstein-Barr virus-encoded RNA (EBER) in situ hybridization experiments, T-cell receptor (TCR) gene rearrangement, RT-PCR tests and the Elisa assay were carried out.

Results

The main clinical manifestations were papulovesicular lesions and ulcers on the face, neck, or trunk. Five cases had systemic symptoms. Three of the deceased patients had significant facial edema, deep body necrosis, and ulceration. The pathological results demonstrated that lymphocytes infiltrated blood vessels and sweat glands in addition to the dermis and subcutaneous tissues. All patients tested positive for CD3 and EBER. Six cases tested positive for TCRβF1, but none tested positive for TCRδ. TCRγ monoclonal rearrangement, strongly positive expression of TIA-1 and a Ki67 proliferation index of 40% occurred in 3 fatal cases. When compared to the survival group, the plasma EBV DNA in the deceased group was considerably higher (P<0.05). IFN-γ and TNF-α cytokine levels in patients were higher than in the control group, particularly in the deceased group (P<0.05). The skin lesions on all patients recovered quickly underwent conservative care. Nonetheless, 3 patients passed away as the disease progressed in its latter stages.

Conclusion

In our cases, the main infiltrating cells were T cells and the dominant lymphocyte subclass was αβT cells. A significant increase in lgE level, plasma EBV DNA, IFN-γ, and TNF-α cytokine levels, decreased hemoglobin level, strongly positive expression of TIA-1, high Ki67 proliferation index, and positive TCR gene rearrangement are all indicators of a poor prognosis.

Infections and immunity: associations with obesity and related metabolic disorders

About one-fourth of the global population is either overweight or obese, both of which increase the risk of insulin resistance, cardiovascular diseases, and infections. In obesity, both immune cells and adipocytes produce an excess of pro-inflammatory cytokines that may play a significant role in disease progression. In the recent coronavirus disease 2019 (COVID-19) pandemic, important pathological characteristics such as involvement of the renin-angiotensin-aldosterone system, endothelial injury, and pro-inflammatory cytokine release have been shown to be connected with obesity and associated sequelae such as insulin resistance/type 2 diabetes and hypertension. This pathological connection may explain the severity of COVID-19 in patients with metabolic disorders. Many studies have also reported an association between type 2 diabetes and persistent viral infections. Similarly, diabetes favors the growth of various microorganisms including protozoal pathogens as well as opportunistic bacteria and fungi. Furthermore, diabetes is a risk factor for a number of prion-like diseases. There is also an interesting relationship between helminths and type 2 diabetes; helminthiasis may reduce the pro-inflammatory state, but is also associated with type 2 diabetes or even neoplastic processes. Several studies have also documented altered circulating levels of neutrophils, lymphocytes, and monocytes in obesity, which likely modifies vaccine effectiveness. Timely monitoring of inflammatory markers (e.g., C-reactive protein) and energy homeostasis markers (e.g., leptin) could be helpful in preventing many obesity-related diseases.

Trypanosoma cruzi Antigenic Proteins Shared with Acute Lymphoblastic Leukemia and Neuroblastoma

Background. Research studies indicate that immunization with protein extracts of Trypanosoma cruzi, the protozoan parasite that causes Chagas disease, prevents the appearance of tumors in 60% of mice injected with the murine lung carcinoma tumor line. The molecular basis of this process is unknown, although the presence of specific antigens in tumor cells and on the surface of T. cruzi suggests an antiparasitic immune response, with an effective cross-reaction against cancer cells, hence the importance to identify the antigens involved and determine their potential as target cells in anticancer therapy. Aim. This study aimed to determine the presence of antigenic proteins of T. cruzi shared with acute lymphoblastic leukemia and neuroblastoma cells. Material and methods. To achieve this, polyclonal antibodies against T. cruzi were developed in rabbits, and reactivity was determined with protein extracts of acute lymphoblastic leukemia cells and neuroblastoma. The immunodetection of five different strains of T. cruzi against anti-T. cruzi polyclonal antibodies was also performed. Conclusion. The study allows the knowledge of the immunological interactions between cancer and parasites to be expanded and, therefore, contributes to the design of more and better projects that improve the therapeutic strategies applied in oncology.

Spatial distribution of incident pediatric Burkitt lymphoma in central and northern Malawi and association with malaria prevalence

BACKGROUND

Burkitt lymphoma (BL) accounts for 90% of pediatric lymphomas in sub-Saharan Africa. Plasmodium falciparum malaria is considered an etiological factor of BL. We describe the geographic distribution of pediatric BL in Malawi and association with P. falciparum malaria prevalence rate (PfPR).

METHODS

We enrolled 220 pathologically confirmed incident pediatric BL cases (2013-2018) into an observational clinical cohort at Kamuzu Central Hospital (KCH) in Lilongwe district. KCH is the main tertiary cancer referral center serving the central and northern regions of Malawi. Using an ecological study design, we calculated district-level annual BL incidence rate using census population estimates. District-level PfPR was extracted from the National Malaria Control Program 2010 report. BL incidence and PfPR maps were constructed in QGIS. Moran's I  test was used to identify BL spatial clusters. Pearson's correlation and multiple linear regression analyses were used to statistically examine the relationship between PfPR and BL.

RESULTS

BL incidence was higher in central region districts (8.2 cases per million) than northern districts (2.9 cases per million) and was elevated in lakeshore districts. Districts with elevated PfPR tended to have elevated BL incidence. A low-risk BL cluster was detected in the north. Statistically, BL incidence was positively correlated with PfPR (r = .77, p < .01). A 1% increase in PfPR predicted an increase in BL incidence of 0.2 cases per million (p = .03), when controlling for travel time from referral district hospital to KCH.

CONCLUSION

Our study supports evidence for an association between P. falciparum and BL and highlights a need to improve geographic accessibility to tertiary cancer services in Malawi's northern region.

Unboxing the molecular modalities of mutagens in cancer

The etiology of the majority of human cancers is associated with a myriad of environmental causes, including physical, chemical, and biological factors. DNA damage induced by such mutagens is the initial step in the process of carcinogenesis resulting in the accumulation of mutations. Mutational events are considered the major triggers for introducing genetic and epigenetic insults such as DNA crosslinks, single- and double-strand DNA breaks, formation of DNA adducts, mismatched bases, modification in histones, DNA methylation, and microRNA alterations. However, DNA repair mechanisms are devoted to protect the DNA to ensure genetic stability, any aberrations in these calibrated mechanisms provoke cancer occurrence. Comprehensive knowledge of the type of mutagens and carcinogens and the influence of these agents in DNA damage and cancer induction is crucial to develop rational anticancer strategies. This review delineated the molecular mechanism of DNA damage and the repair pathways to provide a deep understanding of the molecular basis of mutagenicity and carcinogenicity. A relationship between DNA adduct formation and cancer incidence has also been summarized. The mechanistic basis of inflammatory response and oxidative damage triggered by mutagens in tumorigenesis has also been highlighted. We elucidated the interesting interplay between DNA damage response and immune system mechanisms. We addressed the current understanding of DNA repair targeted therapies and DNA damaging chemotherapeutic agents for cancer treatment and discussed how antiviral agents, anti-inflammatory drugs, and immunotherapeutic agents combined with traditional approaches lay the foundations for future cancer therapies.

Synthesis, Leishmanicidal, Trypanocidal, Antiproliferative Assay and Apoptotic Induction of (2-Phenoxypyridin-3-yl)naphthalene-1(2H)-one Derivatives

The coexistence of leishmaniasis, Chagas disease, and neoplasia in endemic areas has been extensively documented. The use of common drugs in the treatment of these pathologies invites us to search for new molecules with these characteristics. In this research, we report 16 synthetic chalcone derivatives that were investigated for leishmanicidal and trypanocidal activities as well as for antiproliferative potential on eight human cancers and two nontumor cell lines. The final compounds 8−23 were obtained using the classical base-catalyzed Claisen−Schmidt condensation. The most potent compounds as parasiticidal were found to be 22 and 23, while compounds 18 and 22 showed the best antiproliferative activity and therapeutic index against CCRF-CEM, K562, A549, and U2OS cancer cell lines and non-toxic VERO, BMDM, MRC-5, and BJ cells. In the case of K562 and the corresponding drug-resistant K562-TAX cell lines, the antiproliferative activity has shown a more significant difference for compound 19 having 10.3 times higher activity against the K562-TAX than K562 cell line. Flow cytometry analysis using K562 and A549 cell lines cultured with compounds 18 and 22 confirmed the induction of apoptosis in treated cells after 24 h. Based on the structural analysis, these chalcones represent new compounds potentially useful for Leishmania, Trypanosoma cruzi, and some cancer treatments.

Infectious Causes of Neoplasia in the Domestic Cat

Simple Summary

Increasingly, cancers are being linked to infections with viruses, bacteria, and parasites in human medicine. This review summarises the current literature regarding neoplasia occurring in association with infectious diseases in domestic cats. To date, most studies have focused on the role of viruses, especially feline leukaemia virus and feline immunodeficiency virus in association with lymphoma, or the role of papillomavirus in cutaneous and oral neoplasms in cats. Recently, there has been a focus on a potential role of mouse mammary tumour virus in feline mammary carcinoma and lymphoma and studies assessing the potential role of gammaherpes virus and hepadnaviruses in feline neoplasia. Additionally, there has been some focus on potential bacterial and parasitic associations with neoplasia; including reports assessing potential associations between Helicobacter species and gastrointestinal neoplasms, and case reports of neoplasia in association with Platynosomum fastosum and Opisthorchis viverrini.

Abstract

In recent years, growing attention has been paid to the influence/role of infectious diseases in tumour development and progression. Investigations have demonstrated that some infectious organisms can have a direct role in the development of neoplasia, whereas others can predispose to neoplasia by alterations in the immune response, or by creating a pro-inflammatory environment. Feline leukaemia virus was one of the first infectious agents recognised as an oncogenic organism, and along with feline immunodeficiency virus has received the most attention. Since the discovery of this retrovirus, several other organisms have been associated with neoplastic processes in cats, these include gammaherpes virus, mouse mammary tumour virus, papillomaviruses, hepadnavirus, Helicobacter species, and the parasitic infections Platynosomum fastosum and Opisthorchis viverrini. This review summarises the findings to date.

DNA methylation alterations caused by Leishmania infection may generate a microenvironment prone to tumour development

DNA methylation is an epigenetic signature consisting of a methyl group at the 5’ cytosine of CpG dinucleotides. Modifications in DNA methylation pattern have been detected in cancer and infectious diseases and may be associated with gene expression changes. In cancer development DNA methylation aberrations are early events whereas in infectious diseases these epigenetic changes may be due to host/pathogen interaction. In particular, in leishmaniasis, a parasitic disease caused by the protozoan Leishmania, DNA methylation alterations have been detected in macrophages upon infection with Leishmania donovani and in skin lesions from patients with cutaneous leishmaniasis. Interestingly, different types of cancers, such as cutaneous malignant lesions, lymphoma and hepatocellular carcinoma, have been diagnosed in patients with a history of leishmaniasis. In fact, it is known that there exists an association between cancer and infectious diseases. Leishmania infection may increase susceptibility to develop cancer, but the mechanisms involved are not entirely clear. Considering these aspects, in this review we discuss the hypothesis that DNA methylation alterations induced by Leishmania may trigger tumorigenesis in long term infection since these epigenetic modifications may enhance and accumulate during chronic leishmaniasis.

Roles of microRNAs and Long Non-Coding RNAs Encoded by Parasitic Helminths in Human Carcinogenesis

Infectious agents such as viruses, bacteria, and parasites can lead to cancer development. Infection with the helminthic parasite Schistosoma haematobium can cause cancer of the urinary bladder in humans, and infection with the parasites Clonorchis sinensis and Opisthorchis viverrini can promote cholangiocarcinoma. These three pathogens have been categorized as “group 1: carcinogenic to humans” by the International Agency for Research on Cancer (IARC). Additionally, the parasite Schistosoma japonicum has been associated with liver and colorectal cancer and classified as “group 2B: possibly carcinogenic to humans”. These parasites express regulatory non-coding RNAs as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), which modulate genic expression in different biological processes. In this review, we discuss the potential roles of miRNAS and lncRNAs encoded by helminthic parasites that are classified by the IARC as carcinogenic and possibly carcinogenic to humans. The miRNAs of these parasites may be involved in carcinogenesis by modulating the biological functions of the pathogen and the host and by altering microenvironments prone to tumor growth. miRNAs were identified in different host fluids. Additionally, some miRNAs showed direct antitumoral effects. Together, these miRNAs show potential for use in future therapeutic and diagnostic applications. LncRNAs have been less studied in these parasites, and their biological effects in the parasite–host interaction are largely unknown.

Protozoan Intestinal Parasitic Infection in Patients with Hematological Malignancies

The aim of this study was to evaluate the frequency of gastrointestinal protozoan infection in patients with hematological malignancies (HMs) undergoing intensive hemato-oncological treatment and to determine the influence of certain biological factors on the incidence of intestinal parasite infection. Stool samples were collected from hematological malignancy patients (n = 50) hospitalized at the Department of Hematology and Transplantology of the Pomeranian Medical University in Szczecin. The control group consisted of 50 healthy participants. We used a direct smear examination and a commercial immunoenzymatic test. Intestinal protozoans were detected in 16% of patients with hematological malignancies and in 6% of individuals in the control group. In stool samples from patients with HM, cysts of Giardia intestinalis (2%), oocysts of Cryptosporidium spp. (10%), vacuolar forms of potentially pathogenic Blastocystis spp. (2%), and cysts of nonpathogenic Entamoeba coli (2%) were found. Cryptosporidium spp. and Giardia intestinalis coproantigens were detected in 5 (10%) and 1 (2%) patients with HM, respectively. In three participants from the control group, vacuolar forms of Blastocystis spp. were found. In the patients with HM, a significantly higher prevalence of intestinal parasite infection was found in individuals working in the garden without protective gloves and those in contact with animals. In patients with hematological malignancies, intestinal parasites should be excluded, even during intensive chemotherapy treatment.

Genetically modified cancer vaccines: Current status and future prospects

Vaccines can stimulate the immune system to protect individuals from infectious diseases. Moreover, vaccines have also been applied to the prevention and treatment of cancers. Due to advances in genetic engineering technology, cancer vaccines could be genetically modified to increase antitumor efficacy. Various genes could be inserted into cells to boost the immune response, such as cytokines, T cell costimulatory molecules, tumor-associated antigens, and tumor-specific antigens. Genetically modified cancer vaccines utilize innate and adaptive immune responses to induce durable antineoplastic capacity and prevent the recurrence. This review will discuss the major approaches used to develop genetically modified cancer vaccines and explore recent advances to increase the understanding of engineered cancer vaccines.

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 Association of Microbiome Dysbiosis With Colorectal Cancer

Many studies have been conducted to identify the causative organisms in colorectal cancer (CRC) and compare the microbiota of healthy individuals and those with CRC. The pathways by which the microbiota promotes CRC development are not yet fully understood. The hypothesized mechanisms include damage to the DNA, production of carcinogenic metabolites, and promotion of chronic inflammation. In a state of dysbiosis, the gut loses protective bacteria and is enriched with pathogenic and cancer-promoting bacteria, which promotes functions associated with cancer such as angiogenesis, loss of apoptosis, and cell proliferation. We have established a strong link between microbiota dysbiosis and certain species of bacteria and even viruses involved in tumorigenesis. In this review, we look at some of the major identified species and how they are related to CRC. Future research should include and even focus on mycobiome and virome on CRC development. Due to the diversity of the gut microbiome, there is a high possibility that the gain and loss of bacteria and their metabolic functions lead to CRC.

Functional roles of cytokines in infectious disease associated colorectal carcinogenesis

Infection processes induce various soluble factors that are carcinogens in humans; therefore, research into the soluble factors of chronic disease released from cells that have been infected with parasites is warranted. Parasitic infections in host cells release high levels of IFNγ. Studies have hypothesised that parasitosis-associated carcinogenesis might be analogous to colorectal cancers developed from inflammatory bowel diseases, whereby various cytokines and chemokines are secreted during chronic inflammation. IL-18 and IL-21 are other factors that might be involved in the development of colorectal cancer in schistosomiasis patients and patients with other infections. IL-21 has profound effects on tumour growth and immunosurveillance of colitis-associated tumourigenesis, thereby emphasising its involvement in the pathogenesis of colorectal cancer. The prominent role of IL-21 in antitumour effects greatly depends on the enhanced cytolytic activity of NK cells and the pathogenic role of IL-21, which is often associated with enhanced risks of cancer and chronic inflammatory processes. As IL-15 is also related to chronic disease, it is believed to also play a role in the antitumour effect of colorectal carcinogenesis. IL-15 generates and maintains long-term CD8⁺ T cell immunity against T. gondii to control the infection of intracellular pathogens. The lack of IL-15 in mice contributes to the downregulation of the IFNγ-producing CD4⁺ T cell response against acute T. gondii infection. IL-15 induces hyperplasia and supports the progressive growth of colon cancer via multiple functions. The limited role of IL-15 in the development of NK and CD8⁺ T cells suggests that there may be other cytokines compensating for the loss of the IL-15 gene.

Quantitative cytokine level of TNF-α, IFN-γ, IL-10, TGF-β and circulating Epstein-Barr virus DNA load in individuals with acute Malaria due to P. falciparum or P. vivax or double infection in a Malaria endemic region in Indonesia

Plasmodium falciparum Malaria and Epstein-Barr Virus (EBV) infection are risk factors in the development of Burkitt’s lymphoma. In Indonesia, 100% of the population is persistently infected with EBV early in life and at risk of developing EBV-linked cancers. Currently, 10.7 million people in Indonesia are living in Malaria-endemic areas. This cross-sectional study was initiated to investigate how acute Malaria dysregulates immune control over latent EBV infection. Using blood and plasma samples of 68 patients with acute Malaria and 27 healthy controls, we measured the level of parasitemia for each plasmodium type (P. falciparum, P. vivax, and mixed) by microscopy and rapid test. The level of 4 regulatory cytokines was determined by quantitative ELISA and the level of circulating EBV genome by real-time PCR targeting the single copy EBNA-1 sequence. All Plasmodium-infected cases had high-level parasitemia (>1000 parasites/ul blood) except for one case. EBV-DNA levels were significantly more elevated in P. falciparum and P. vivax infections (P<0.05) compared to controls. EBV-DNA levels were not related to age, gender, Malaria symptoms, or plasmodium type. TNF-α and IL-10 levels were increased in Malaria cases versus controls, but IFN-γ and TGF- β levels were comparable between the groups. Only TNF-α levels in P. falciparum cases showed a clear correlation with elevated EBV DNA levels (R² = 0.8915). This is the first study addressing the relation between EBV (re)activation and cytokine responses during acute Malaria, revealing a clear correlation between pro-inflammatory cytokine TNF-α and EBV-DNA levels, specifically in P. falciparum cases, suggesting this cytokine to be key in dysregulating EBV homeostasis during acute P. falciparum Malaria.

Host DNA repair response to oxidative damage is modulated by Trypanosoma cruzi in a strain-dependent manner

The conservation of genomic integrity and stability is essential for cell survival. DNA Damage Responses (DDRs) are considered of paramount importance for all living beings and involve mechanisms of cell cycle regulation and damage-specific DNA repair pathways. Hydrogen peroxide (H₂O₂) is a compound that, in supraphysiological concentrations, damages biomolecules including the DNA, causing base modifications and strand breaks. There is evidence that Trypanosoma cruzi, the protozoan that causes Chagas disease, interferes in the host cell's DNA metabolism. In order to investigate the influence of T. cruzi infection over the host cell capacity to withstand and repair DNA damage, we analyzed L6 cells infected with Berenice, and Colombiana T. cruzi strains according to their viability, proliferation, morphology, DNA degradation, expression of DNA repair, and cell cycle genes following H₂O₂ treatment. It was noted that T. cruzi infection might act as either a stressor or a protective element of host DNA, depending on the strain and H₂O₂ concentration. Cells infected with Berenice strain and treated with 0.8 mM H₂O₂ presented a reduced DNA damage response intensity (e.g., BER and HR). Infection with T. cruzi Colombiana prevented the activation of DNA repair pathways in response to 0.8mM and 1.6mM H₂O₂ (NER and MMR). Nevertheless, since cellular viability was not significantly compromised in Colombiana-infected cells following the oxidative insult, it is possible that the parasite directly influenced the host DNA repair machinery. Our results support the notion that T. cruzi is able to modulate the host cell DNA metabolism in a strain-dependent manner, an event which can be explored in future drug development strategies.

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, mostly 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.

Anti-osteosarcoma effect of antiserum against cross antigen TPD52 between osteosarcoma and Trichinella spiralis

BACKGROUND

Trichinella spiralis (T. spiralis) is a parasite occurring worldwide that has been proven to have antitumour ability. However, studies on the antitumour effects of cross antigens between the tumour and T. spiralis or antibodies against cross antigens between tumours and T. spiralis are rare.

METHODS

To study the role of cross antigens between osteosarcoma and T. spiralis, we first screened the cDNA expression library of T. spiralis muscle larvae to obtain the cross antigen gene tumour protein D52 (TPD52), and prepared fusion protein TPD52 and its antiserum. The anti-osteosarcoma effect of the anti-TPD52 antiserum was studied using cell proliferation and cytotoxicity assays as well as in vivo animal models; preliminary data on the mechanism were obtained using western blot and immunohistochemistry analyses.

RESULTS

Our results indicated that TPD52 was mainly localized in the cytoplasm of MG-63 cells. Anti-TPD52 antiserum inhibited the proliferation of MG-63 cells and the growth of osteosarcoma in a dose-dependent manner. The tumour inhibition rate in the 100 μg treatment group was 61.95%. Enzyme-linked immunosorbent assay showed that injection of anti-TPD52 antiserum increased the serum levels of IFN-γ, TNF-α, and IL-12 in nude mice. Haematoxylin and eosin staining showed that anti-TPD52 antiserum did not cause significant pathological damage. Apoptosis of osteosarcoma cells was induced by anti-TPD52 antiserum in vivo and in vitro.

CONCLUSIONS

Anti-TPD52 antiserum exerts an anti-osteosarcoma effect by inducing apoptosis without causing histopathological damage.

Schistosoma mansoni infection and the occurrence, characteristics, and survival of patients with hepatocellular carcinoma: an observational study over a decade

Schistosoma mansoni infection (SMI) is suspected to be directly and indirectly involved in hepato-carcinogenesis. This study evaluated the association of a previous SMI with hepatocellular carcinoma (HCC) development, patients, tumor characteristics, treatment outcomes, and survival. This observational study included patients with HCC with and without previous SMI who presented to the multidisciplinary HCC clinic, Kasr-Alainy hospital (November 2009 to December 2019). It also included 313 patients with liver cirrhosis without HCC. Clinical and laboratory features of the patients (complete blood count, liver/renal functions , alpha-fetoprotein, and hepatitis B/C status), tumor characteristics (Triphasic CT and/or dynamic MRI), liver stiffness (transient elastography), HCC treatment outcome, and overall survival were studied. This study included 1446 patients with HCC; 688(47.6%) composed group-1, defined by patients having a history of SMI, and 758(52.4%) were in group-2 and without history of SMI. Male sex, smoking, diabetes mellitus, splenomegaly, deteriorated performance status, synthetic liver functions, and platelet count were significantly higher in group-1. The groups did not differ with regard to liver stiffness, tumor characteristics, or the occurrence of post-HCC treatment hepatic decompensation or recurrence. HCC treatment response was better in group-2. Group-1 showed lower sustained virological response to hepatitis C direct-acting antivirals (DAAs) compared with group-2 (60% versus 84.3%, respectively, P = 0.027). Prior SMI was associated with HCC (adjusted odds ratio = 1.589, 95% confidence interval = 1.187-2.127), and it was concluded that it increases the risk of HCC. In addition, it significantly affects the performance status, laboratory characteristics, response to DAAs, and overall survival.

Does Schistosoma Mansoni Facilitate Carcinogenesis?

Schistosomiasis is one of the most prominent parasite-induced infectious diseases, causing tremendous medical and socioeconomic problems. Current studies have reported on the spread of endemic regions and the fear of development of resistance against praziquantel, the only effective drug available. Among the Schistosoma species, only S. haematobium is classified as a Group 1 carcinogen (definitely cancerogenic to humans), causing squamous cell carcinoma of the bladder, whereas infection with S. mansoni is included in Group 3 of carcinogenic hazards to humans by the International Agency for Research on Cancer (IARC), indicating insufficient evidence to determine its carcinogenicity. Nevertheless, although S. mansoni has not been discussed as an organic carcinogen, the multiplicity of case reports, together with recent data from animal models and cell culture experiments, suggests that this parasite can predispose patients to or promote hepatic and colorectal cancer. In this review, we discuss the current data, with a focus on new developments regarding the association of S. mansoni infection with human cancer and the recently discovered biomolecular mechanisms by which S. mansoni may predispose patients to cancer development and carcinogenesis.

Comorbid early esophageal cancer and Gongylonema pulchrum infection: a case report

Background

Gongylonema pulchrum is a zoonotic parasite rarely found in humans. To date, there have been no reports on the carcinogenic properties of G. pulchrum, and there are few reports overall on the relationship between esophageal cancer and parasites.

Case presentation

This report describes the first case of esophageal gongylonemiasis coexisting with early esophageal cancer. The patient had no high-risk factors for esophageal cancer, such as smoking, flushing after drinking, or tumor history. We speculate the existence of unknown links between esophageal cancer and parasitic infection in this patient.

Discussion and conclusions

We report the first case of a human presenting both esophageal G. pulchrum infection and esophageal squamous cell carcinoma with the hope that it may provide evidence for a new hypothesis of tumorigenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01873-8.

A Schistosoma japonicum MicroRNA Exerts Antitumor Effects Through Inhibition of Both Cell Migration and Angiogenesis by Targeting PGAM1

MicroRNA (miRNA) is an important regulator for gene expression. Recent studies showed that some heterogenous miRNAs derived from both parasite and plant can regulate expression of mammalian gene in a cross-species or even a cross-kingdom manner. Here, we identified a Schistosoma japonicum miRNA (designated as sja-miR-61) that is present in the hepatocyte of mice infected with the parasite. The sja-miR-61 mimics significantly inhibited the migration of both mouse and human hepatoma cells in vitro. In a xenograft animal model, significant reductions of the tumor volume and weight were observed in mice inoculated with hepatoma cells transfected with sja-miR-61 mimics compared to the controls. We found that the in vivo inhibition of tumor growth was through its anti-angiogenesis activity. Mechanically, we identified the phosphoglycerate mutase 1 (PGAM1) gene as a target of sja-miR-61 and found that the sja-miR-61-mediated suppression of cell migration and anti-angiogenesis by cross-species down-regulation of PGAM1 expression. These data indicated that sja-miR-61 is a tumor suppressor miRNA that may have therapeutic potential for human cancers.

Pathogens and Carcinogenesis: A Review

Cancer is a global health problem associated with genetics and unhealthy lifestyles. Increasingly, pathogenic infections have also been identified as contributors to human cancer initiation and progression. Most pathogens (bacteria, viruses, fungi, and parasites) associated with human cancers are categorized as Group I human carcinogens by the International Agency for Research on Cancer, IARC. These pathogens cause carcinogenesis via three known mechanisms: persistent infection that cause inflammation and DNA damage, initiation of oncogene expression, and immunosuppression activity of the host. In this review, we discuss the carcinogenesis mechanism of ten pathogens, their implications, and some future considerations for better management of the disease. The pathogens and cancers described are Helicobacter pylori (gastric cancer), Epstein-Barr virus (gastric cancer and lymphoma), Hepatitis B and C viruses (liver cancer), Aspergillus spp. (liver cancer), Opisthorchis viverrine (bile duct cancer), Clonorchis sinensis (bile duct cancer), Fusobacterium nucleatum (colorectal cancer), Schistosoma haematobium (bladder cancer); Human Papillomavirus (cervical cancer), and Kaposi's Sarcoma Herpes Virus (Kaposi's sarcoma).

Natural Products: Implication in Cancer Prevention and Treatment through Modulating Various Biological Activities

Cancer is one of the most leading causes of death worldwide. It is one of the primary global diseases that cause morbidity and mortality in millions of people. It is usually caused by different carcinogenic agents that damage the genetic material and alter the cell signaling pathways. Carcinogens are classified into two groups as genotoxic and non-genotoxic agents. Genotoxic carcinogens are capable of directly altering the genetic material, while the non-genotoxic carcinogens are capable of producing cancer by some secondary mechanisms not related to direct gene damage. There is undoubtedly the greatest need to utilize some novel natural products as anticancer agents, as these are within reach everywhere. Interventions by some natural products aimed at decreasing the levels and conditions of these risk factors can reduce the frequency of cancer incidences. Cancer is conventionally treated by surgery, radiation therapy and chemotherapy, but such treatments may be fast-acting and causes adverse effects on normal tissues. Alternative and innovative methods of cancer treatment with the least side effects and improved efficiency are being encouraged. In this review, we discuss the different risk factors of cancer development, conventional and innovative strategies of its management and provide a brief review of the most recognized natural products used as anticancer agents globally.

The Role of Viruses in Carcinogenesis and Molecular Targeting: From Infection to Being a Component of the Tumor Microenvironment

About a tenth of all cancers are caused by viruses or associated with viral infection. Recent global events including the coronavirus disease-2019 (COVID-19) pandemic means that human encounter with viruses is increased. Cancer development in individuals with viral infection can take many years after infection, demonstrating that the involvement of viruses in cancer development is a long and complex process. This complexity emanates from individual genetic heterogeneity and the many steps involved in cancer development owing to viruses. The process of tumorigenesis is driven by the complex interaction between several viral factors and host factors leading to the creation of a tumor microenvironment (TME) that is ideal and promotes tumor formation. Viruses associated with human cancers ensure their survival and proliferation through activation of several cellular processes including inflammation, migration, and invasion, resistance to apoptosis and growth suppressors. In addition, most human oncoviruses evade immune detection and can activate signaling cascades including the PI3K-Akt-mTOR, Notch and Wnt pathways associated with enhanced proliferation and angiogenesis. This expert review examines and synthesizes the multiple biological factors related to oncoviruses, and the signaling cascades activated by these viruses contributing to viral oncogenesis. In particular, I examine and review the Epstein-Barr virus, human papillomaviruses, and Kaposi's sarcoma herpes virus in a context of cancer pathogenesis. I conclude with a future outlook on therapeutic targeting of the viruses and their associated oncogenic pathways within the TME. These anticancer strategies can be in the form of, but not limited to, antibodies and inhibitors.

Global epidemiology of Giardia duodenalis infection in cancer patients: a systematic review and meta-analysis

Background

Application of chemotherapeutics in cancer patients may provide an immunosuppressive milieu, favourable for parasitic infections. Giardia duodenalis is an important zoonotic intestinal parasite responsible for diarrhoea in humans worldwide.

Methods

The present systematic review and meta-analysis was conducted to estimate the prevalence of G. duodenalis and respective odds ratios (ORs) in cancer patients around the globe. Four online databases—PubMed, Scopus, Web of Science and Google Scholar—were carefully explored for relevant literature without time limitation until 28 November 2020. Meta-analysis was done based on a random effects model to pool the estimations and define 95% confidence intervals (CIs).

Results

The overall weighted prevalence of G. duodenalis infection in cancer patients was calculated to be 6.9% (95% CI 0.5 to 9.3) globally, based on data from 32 studies. Although not statistically significant, eight case–control studies revealed that cancer patients were 1.24 times (95% CI 0.66 to 2.31; p=0.501) more exposed to G. duodenalis infection than healthy controls. Moreover, the prevalence of infection was not significantly associated with quantitative variables, including publication year (regression coefficient −0.0135, p=0.578), sample size (regression coefficient −0.0007, p=0.074) and human development index (regression coefficient −1.6263, p=0.419). Also, subgroup analysis of the pooled G. duodenalis infection was performed for publication year, World Health Organization regions, countries, continents, cancer types and country income.

Conclusions

Altogether, the epidemiology of G. duodenalis infection and its associated risk factors in immunocompromised individuals, especially cancer patients, is still open to question and deserves comprehensive investigations.

Repositioning of Antiparasitic Drugs for Tumor Treatment

Drug repositioning is a strategy for identifying new antitumor drugs; this strategy allows existing and approved clinical drugs to be innovatively repurposed to treat tumors. Based on the similarities between parasitic diseases and cancer, recent studies aimed to investigate the efficacy of existing antiparasitic drugs in cancer. In this review, we selected two antihelminthic drugs (macrolides and benzimidazoles) and two antiprotozoal drugs (artemisinin and its derivatives, and quinolines) and summarized the research progresses made to date on the role of these drugs in cancer. Overall, these drugs regulate tumor growth via multiple targets, pathways, and modes of action. These antiparasitic drugs are good candidates for comprehensive, in-depth analyses of tumor occurrence and development. In-depth studies may improve the current tumor diagnoses and treatment regimens. However, for clinical application, current investigations are still insufficient, warranting more comprehensive analyses.

Possible Association and Risk Factors of Blastocystis Infection and Colorectal Cancers in Western Iran

Background: Recently, infection has been considered one of the most important causes of cancers because a large number of cases of cancer with infectious origin was reported. Objectives: The present investigation aimed to evaluate the prevalence and risk factors of Blastocystis hominis infection in patients with colorectal cancer in comparison to healthy individuals. Methods: The present descriptive case-control study was performed on 67 healthy individuals and 67 patients with colorectal cancers attending the general hospitals of Lorestan Province, Western Iran from October 2017 to August 2018. Colorectal cancers were diagnosed by an experienced gastroenterologist. A fresh stool specimen was collected from each subject in a sterile labeled container. The collected specimens were tested microscopically using saline and iodine wet preparations, then stained with trichrome stain according to the manufacturer’s instruction to find the cases of B. hominis forms. The DNA of the samples was extracted and specific primer-polymerase chain reaction (PCR) was performed. Results: Among the colorectal cancer patients, B. hominis was found in 16 (23.9%) patients, whereas of 67 healthy participants, 6 (9%) cases were found, indicating a significant difference (P < 0.001) in the prevalence B. hominis among the participants in the case and control groups. By the multifactorial logistic regression models, agriculture activity (0.24; 95% CI: 0.075 - 0.809), as well as consumption of unwashed fruit and vegetables (0.136; 95% CI: 0.040 - 0.459), were significantly related to the prevalence of B. homonis infection. All 22 positive samples (16 patients and 6 (9%) healthy people) were also positive by PCR method, indicating the presence of B. hominis and accuracy of microscopic examination, extraction, and PCR reaction. Conclusions: The obtained findings revealed that B. hominis may strongly link with human colorectal cancers given novel information about the important role of B. hominis in the progress of colorectal cancer. Nevertheless, more investigations are required to obtain accurate information about this suggestion.

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.

Trematode Proteomics: Recent Advances and Future Directions

Trematodes cause disease in millions of people worldwide, but the absence of commercial vaccines has led to an over-reliance on a handful of monotherapies to control infections. Since drug-resistant fluke populations are emerging, a deeper understanding of parasite biology and host interactions is required to identify new drug targets and immunogenic vaccine candidates. Mass spectrometry-based proteomics represents a key tool to that end. Recent studies have capitalised on the wider availability of annotated helminth genomes to achieve greater coverage of trematode proteomes and discover new aspects of the host-parasite relationship. This review focusses on these latest advances. These include how the protein components of fluke extracellular vesicles have given insight into their biogenesis and cellular interactions. In addition, how the integration of transcriptome/proteome datasets has revealed that the expression and secretion of selected families of liver fluke virulence factors and immunomodulators are regulated in accordance with parasite development and migration within the mammalian host. Furthermore, we discuss the use of immunoproteomics as a tool to identify vaccine candidates associated with protective antibody responses. Finally, we highlight how established and emerging technologies, such as laser microdissection and single-cell proteomics, could be exploited to resolve the protein profiles of discrete trematode tissues or cell types which, in combination with functional tools, could pinpoint optimal targets for fluke control.

Schistosome Infection and Schistosome-Derived Products as Modulators for the Prevention and Alleviation of Immunological Disorders

Parasitic helminths, comprising the flatworms (tapeworms and flukes) and nematodes (roundworms), have plagued humans persistently over a considerable period of time. It is now known that the degree of exposure to these and other pathogens inversely correlates with the incidence of both T helper 1 (Th1)-mediated autoimmunity and Th2-mediated allergy. Accordingly, there has been recent increased interest in utilizing active helminth worm infections and helminth-derived products for the treatment of human autoimmune and inflammatory diseases and to alleviate disease severity. Indeed, there is an accumulating list of novel helminth derived molecules, including proteins, peptides, and microRNAs, that have been shown to exhibit therapeutic potential in a variety of disease models. Here we consider the blood-dwelling schistosome flukes, which have evolved subtle immune regulatory mechanisms that promote parasite survival but at the same time minimize host tissue immunopathology. We review and discuss the recent advances in using schistosome infection and schistosome-derived products as therapeutics to treat or mitigate human immune-related disorders, including allergic asthma, arthritis, colitis, diabetes, sepsis, cystitis, and cancer.