Farming, Pesticides, and Brain Cancer: A 20-Year Updated Systematic Literature Review and Meta-Analysis

Pre-mating exposure with hesperidin protects N-ethyl-N-nitrosourea-induced neurotoxicity and congenital abnormalities in next generation of mice as a model of glioma

Chemical carcinogen-induced oxidative stress has a key role in cell signaling linked to the development of cancer. Oxidative stress leads to oxidative damage to cellular membranes, proteins, chromosomes and genetic material. It is thought that compounds like hesperidin with high antioxidant and anticancer potential can reduce development of cancer induced by chemical carcinogens via neutralizing their oxidative damages. We investigated protective effect of hesperidin against N-Ethyl-N-Nitrosourea (ENU)-induced neurotoxicity, congenital abnormalities and possible brain cancer after exposure of mice during pregnancy as model of glioma. The mice were divided to four groups; control (normal saline), ENU (40 mg/kg daily for three consecutive days from the 17th to the 19th of pregnancy), hesperidin (pretreated with 25 mg/kg for 30 consecutive days, before mating) + ENU and hesperidin alone. Developmental toxicity parameters (the number of pregnant mice, stillbirths, abortion, live and dead offspring), behavioral tests (novel object recognition, open field and elevated plus maze) were performed. Moreover, the activity of butrylcholinesterase and acetylcholinesterase enzymes, oxidative markers and histopathological abnormalities were detected in brain tissue. Our data showed that conversely, the pretreatment of hesperidin reduces various degrees of developmental toxicity, neurobehavioral dysfunction, neurotoxicity, oxidative stress and histopathological abnormalities induced by ENU as a neurotoxic and carcinogenic agent in the next generation. In conclusion, pre-mating exposure with hesperidin may open new avenues for prevention of primary brain cancer in next generation and could be valuable for enhancing the antioxidant defense and minimizing the developmental and neurotoxicity of DNA alkylating agents.

Principles in the Management of Glioblastoma

Glioblastoma, the most aggressive and common malignant primary brain tumour, is characterized by infiltrative growth, abundant vascularization, and aggressive clinical evolution. Patients with glioblastoma often face poor prognoses, with a median survival of approximately 15 months. Technological progress and the subsequent improvement in understanding the pathophysiology of these tumours have not translated into significant achievements in therapies or survival outcomes for patients. Progress in molecular profiling has yielded new omics data for a more refined classification of glioblastoma. Several typical genetic and epigenetic alterations in glioblastoma include mutations in genes regulating receptor tyrosine kinase (RTK)/rat sarcoma (RAS)/phosphoinositide 3-kinase (PI3K), p53, and retinoblastoma protein (RB) signalling, as well as mutation of isocitrate dehydrogenase (IDH), methylation of O6-methylguanine-DNA methyltransferase (MGMT), amplification of epidermal growth factor receptor vIII, and codeletion of 1p/19q. Certain microRNAs, such as miR-10b and miR-21, have also been identified as prognostic biomarkers. Effective treatment options for glioblastoma are limited. Surgery, radiotherapy, and alkylating agent chemotherapy remain the primary pillars of treatment. Only promoter methylation of the gene MGMT predicts the benefit from alkylating chemotherapy with temozolomide and it guides the choice of first-line treatment in elderly patients. Several targeted strategies based on tumour-intrinsic dominant signalling pathways and antigenic tumour profiles are under investigation in clinical trials. This review explores the potential genetic and epigenetic biomarkers that could be deployed as analytical tools in the diagnosis and prognostication of glioblastoma. Recent clinical advancements in treating glioblastoma are also discussed, along with the potential of liquid biopsies to advance personalized medicine in the field of glioblastoma, highlighting the challenges and promises for the future.

Agricultural exposures and risk of childhood neuroblastoma: a systematic review and meta-analysis

While neuroblastoma accounts for an estimated 8% of childhood cancers, it causes about 15% of childhood cancer deaths in the United States. The role of agricultural exposures in the development of neuroblastoma is unclear. We conducted a systematic review and meta-analysis of studies examining the relationship between agricultural exposures and neuroblastoma. MEDLINE, EMBASE, Scopus, and Google Scholar were searched in February 2022, identifying 742 publications. Seventeen articles met the inclusion criteria; all were published between 1985 and 2020 and included 14 case-control, one cross-sectional, and two cohort studies. Random and fixed effects models were used to calculate summary odds ratios (sORs) and 95% confidence intervals (CIs). An increased odds of developing neuroblastoma with parental exposure to any pesticides (sOR = 1.25, 95% CI: 1.03-1.48; 4 studies), insecticides (sOR = 1.55, 95% CI: 1.19-1.91; 3 studies), and residential exposure to crops/vegetables (sOR = 1.04, 95% CI: 1.01-1.06; 2 studies) was seen. Heterogeneity was low in all analyses, and no publication bias was evident. No significant associations were found with agricultural occupations, herbicides, and agricultural dusts. The studies were limited by exposure measurements and small sample sizes. Further studies are needed to explore mechanisms in the development of neuroblastoma in children with parental agricultural exposures, especially pesticides, and to improve methods of measuring agricultural-related exposures.

Evaluating the perceptions of pesticide use, safety, and regulation and identifying common pesticide-related topics on Twitter

Synthetic pesticides are important agricultural tools that increase crop yield and help feed the world's growing population. These products are also highly regulated to balance benefits and potential environmental and human risks. Public perception of pesticide use, safety, and regulation is an important topic necessitating discussion across a variety of stakeholders from lay consumers to regulatory agencies since attitudes toward this subject could differ markedly. Individuals and organizations can perceive the same message(s) about pesticides differently due to prior differences in technical knowledge, perceptions, attitudes, and individual or group circumstances. Social media platforms, like Twitter, include both individuals and organizations and function as a townhall where each group promotes their topics of interest, shares their perspectives, and engages in both well-informed and misinformed discussions. We analyzed public Twitter posts about pesticides by user group, time, and location to understand their communication behaviors, including their sentiments and discussion topics, using machine learning-based text analysis methods. We extracted tweets related to pesticides between 2013 and 2021 based on relevant keywords developed through a "snowball" sampling process. Each tweet was grouped into individual versus organizational groups, then further categorized into media, government, industry, academia, and three types of nongovernmental organizations. We compared topic distributions within and between those groups using topic modeling and then applied sentiment analysis to understand the public's attitudes toward pesticide safety and regulation. Individual accounts expressed concerns about health and environmental risks, while industry and government accounts focused on agricultural usage and regulations. Public perceptions are heavily skewed toward negative sentiments, although this varies geographically. Our findings can help managers and decision-makers understand public sentiments, priorities, and perceptions and provide insights into public discourse on pesticides. Integr Environ Assess Manag 2023;19:1581-1599. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Cancer risks in a population-based study of agricultural workers: results from the Taiwan's Farmers and Health Cohort study

OBJECTIVE

The purpose of this study was to assess cancer risk among agricultural workers compared to the general population.

METHODS

The study utilized data from Farmers' Health Insurance (FHI) in Taiwan, which enrolled agricultural workers (N=1 175 149). The enrolled workers were matched to a general population (N=1 175 149) of the same age, gender, township, and enrollment year. The study population was linked to the National Cancer Registry to identify new cancer cases between 2000 and 2018. The Cox proportional hazards model was used to estimate the hazard ratio and 95% confidence interval for outcomes.

RESULTS

During the study period, 136 913 new cancers among agricultural workers were identified. The study found that male farmers had an increased cancer risk, including lymphocytic leukemia, chronic myelogenous leukemia, non-Hodgkin's lymphoma (NHL), oral cancer, lip cancer, esophagus cancer, rectum and rectosigmoid junction cancer, liver and intrahepatic bile duct cancer, lung cancer, trachea and bronchi cancer, and other non-melanoma skin cancer, even when considering the latency period. Female farmers had an elevated risk of multiple myeloma and other non-melanoma skin cancer. Moreover, only lymphoma, NHL, other lymphoid, and multiple myeloma, were both found to occur at different insurance periods.

CONCLUSIONS

This study provides farmer cancer patterns and risk, adding to the evidence that farmers are at increased risk of certain types of cancer, especially for hematological cancers. As exposure varies by farm operation type, individual farmer exposure may vary widely. Further understanding of the complex relationship between occupational exposure, environmental factors, and lifestyle factors is needed.

Research of Pesticide Metabolites in Human Brain Tumor Tissues by Chemometrics-Based Gas Chromatography-Mass Spectrometry Analysis for a Hypothetical Correlation between Pesticide Exposure and Risk Factor of Central Nervous System Tumors

Pesticides are widely used, resulting in continuing human exposure with potential health impacts. Some exposures related to agricultural works have been associated with neurological disorders. Since the 2000s, the hypothesis of the role of pesticides in the occurrence of central nervous system (CNS) tumors has been better documented in the literature. However, the etiology of childhood brain cancers still remains largely unknown. The major objective of this work was to assess the potential role of pesticide exposure as a risk factor for CNS tumors based on questionnaires and statistical analysis of information collected from patients hospitalized in the Neurosurgery Department of the Habib Bourguiba Hospital Medium in Sfax, Tunisia, during the period from January 1, 2022, to May 31, 2023. It also aimed to develop a simple and rapid analytical method by the gas chromatography-mass spectrometry technique for the research traces of pesticide metabolites in some collected human brain tumor tissues in order to more emphasize our hypothesis for such a correlation between pesticide exposure and brain tumor development. Patients with a history of high-risk exposure were selected to conduct further analysis. Chemometric methods were adapted to discern intrinsic variation between pathological and control groups and ascertain effective separation with the identification of differentially expressed metabolites accountable for such variations. Three samples revealed traces of pesticide metabolites that were mostly detected at an early age. The histopathological diagnosis was medulloblastoma for a 10-year-old child and high-grade gliomas for 27- and 35-year-old adults. The bivariate analyses (odds ratio >1 and P value <5%) confirmed the great probability of developing cancer by an exposure case. The Cox proportional hazards model revealed the risk of carcinogenicity beyond the age of 50 as a long-term effect of pesticide toxicity. Our study supports the correlation between pesticide exposure and the risk of development of human brain tumors, suggesting that preconception pesticide exposure, and possibly exposure during pregnancy, is associated with an increased childhood brain tumor risk. This hypothesis was enhanced in identifying traces of metabolites from the carbamate insecticide class known for their neurotoxicity and others from pyridazinone, organochlorines (OCs), triazole fungicide, and N-nitroso compounds known for their carcinogenicity. The 2D-OXYBLOT analysis confirmed the neurotoxicity effect of insecticides to induce oxidative damage in CNS cells. Aldicarb was implicated in brain carcinogenicity confirmed by the identification of oxime metabolites in a stress degradation study. Revealing "aziridine" metabolites from the OC class may better emphasize the theory of detecting traces of pesticide metabolites at an early age. Overall, our findings lead to the recommendation of limiting the residential use of pesticides and the support of public health policies serving this objective that we need to be vigilant in the postmarketing surveillance of human health impacts.

International patterns and trends in the brain cancer incidence and mortality: An observational study based on the global burden of disease

Background

Brain cancer is a serious issue in the global burden of diseases. This observational research aimed to assess trends of the brain cancer incidence and mortality in the world in the period 1990-2019.

Methods

Brain cancer incidence and mortality data were retrieved from the Global Burden of Disease 2019 study database. The joinpoint regression analysis was done to assess the brain cancer indicence and mortality trends: the average annual percent change (AAPC) along with its 95% confidence interval (95% CI) was calculated.

Results

In both sexes, the highest age-standardized rates of incidence and mortality were found in high-income regions (Europe and America), while the lowest were observed in the African Region. A significant rise in brain cancer incidence rates both in males and females was observed in all regions, with one exception of a significantly decreased trend only among males in the South-East Asia Region. Among countries with increased trends in incidence and mortality from brain cancer, Cuba experienced the most marked increase in both incidence (AAPC = +5.7% in males and AAPC = +5.4% in females) and mortality rates (AAPC = +5.5% in males and AAPC = +5.1% in females). Among countries that experienced a decline in brain cancer incidence and mortality, Hungary and Greenland showed the most marked decline in both sexes (equally by -1.0%).

Conclusion

Brain cancer shows increasing global incidence rates in both sexes and represents a priority for prevention and further research.

Impacts of Environmental Pollution on Brain Tumorigenesis

Pollutants consist of several components, known as direct or indirect mutagens, that can be associated with the risk of tumorigenesis. The increased incidence of brain tumors, observed more frequently in industrialized countries, has generated a deeper interest in examining different pollutants that could be found in food, air, or water supply. These compounds, due to their chemical nature, alter the activity of biological molecules naturally found in the body. The bioaccumulation leads to harmful effects for humans, increasing the risk of the onset of several pathologies, including cancer. Environmental components often combine with other risk factors, such as the individual genetic component, which increases the chance of developing cancer. The objective of this review is to discuss the impact of environmental carcinogens on modulating the risk of brain tumorigenesis, focusing our attention on certain categories of pollutants and their sources.

Agricultural activities and risk of central nervous system tumors among French farm managers: Results from the TRACTOR project

The etiology of central nervous system (CNS) tumors is complex and involves many suspected risk factors. Scientific evidence remains insufficient, in particular in the agricultural field. The goal of our study was to investigate associations between agricultural activities and CNS tumors in the entire French farm manager workforce using data from the TRACTOR project. The TRACTOR project hold a large administrative health database covering the entire French agricultural workforce, over the period 2002-2016, on the whole French metropolitan territory. Associations were estimated for 26 activities and CNS tumors using Cox proportional hazards model, with time to first CNS tumor insurance declaration as the underlying timescale, adjusting for sex, age and geographical area. There were 1017 cases among 1 036 069 farm managers, including 317 meningiomas and 479 gliomas. Associations varied with tumor types, sex and types of crop and animal farming. Analyses showed several increased risks of CNS tumors, in particular for animal farming. The main increases in risk were observed for meningioma in mixed dairy and cow farming (hazard ratio [HR] = 1.75, 95% confidence interval [CI]: 1.09-2.81) and glioma in pig farming (HR = 2.28, 95% CI: 1.37-3.80). Our study brings new insights on the association of a wide range of agricultural activities and CNS tumor and subtype-specific risks in farm managers. Although these findings need to be corroborated in further studies and should be interpreted cautiously, they could have implications for enhancing CNS tumor surveillance in agriculture.

Is micronucleus assay in oral exfoliated cells a useful biomarker for biomonitoring populations exposed to pesticides? A systematic review with meta-analysis

The systematic review (SR) with meta-analysis aimed to infer if micronucleus assay using oral mucosal cells a useful biomarker for biomonitoring populations continuously exposed to pesticides (EP). The SR has been made in accordance with the PRISMA-P guidelines. The PICOS strategy has focused to answer the following question: "Does exposure to pesticides cause genetic damage in oral cells?" The literature search was made in the following scientific databases: Web of Science, PubMed/Medline, and Scopus. The approach was defined as follows: standardized mean difference (SMD) and 95% confidence intervals (CI). The quality assessment of manuscripts was obtained by the EPHPP (Effective Public Health Practice Project). The GRADE tool was chosen for assessing the quality of evidence. A total of 108 articles were selected in this setting. After screening abstracts and titles, 23 manuscripts were evaluated for eligibility. After reviewing the studies, two were considered weak and 22 were classified as moderate or strong. The meta-analysis data pointed out statistically significant differences in volunteers exposed to EP (SMD = 1.23, 95% CI, 0.69 to 1.77, p < 0.001), with a Tau2 = 1.44; Chi2 = 566.38, and p < 0.001, so that the selected manuscripts were considered heterogeneous and the I2 of 97% indicated high heterogeneity. Taken together, this review was able to validate the micronucleus assay in oral exfoliated cells as a useful biomarker in individuals continuously exposed to EP because the studies categorized as moderate and strong have demonstrated positive response related to mutagenesis.

Risk Factors for Brain Health in Agricultural Work: A Systematic Review

Certain exposures related to agricultural work have been associated with neurological disorders. To date, few studies have included brain health measurements to link specific risk factors with possible neural mechanisms. Moreover, a synthesis of agricultural risk factors associated with poorer brain health outcomes is missing. In this systematic review, we identified 106 articles using keywords related to agriculture, occupational exposure, and the brain. We identified seven major risk factors: non-specific factors that are associated with agricultural work itself, toluene, pesticides, heavy metal or dust exposure, work with farm animals, and nicotine exposure from plants. Of these, pesticides are the most highly studied. The majority of qualifying studies were epidemiological studies. Nigral striatal regions were the most well studied brain area impacted. Of the three human neuroimaging studies we found, two focused on functional networks and the third focused on gray matter. We identified two major directions for future studies that will help inform preventative strategies for brain health in vulnerable agricultural workers: (1) the effects of moderators such as type of work, sex, migrant status, race, and age; and (2) more comprehensive brain imaging studies, both observational and experimental, involving several imaging techniques.