Exposure to environmental chemicals and heavy metals, and risk of pancreatic cancer

Genetic and other risk factors for pancreatic ductal adenocarcinoma (PDAC)

Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed at an advanced stage, resulting in poor prognosis and low 5-year survival rates. While early evidence suggests increased long-term survival in those with screen-detected resectable cancers, surveillance imaging is currently only recommended for individuals with a lifetime risk of PDAC ≥ 5%. Identification of risk factors for PDAC provides opportunities for early detection, risk reducing interventions, and targeted therapies, thus potentially improving patient outcomes. Here, we summarize modifiable and non-modifiable risk factors for PDAC. We review hereditary cancer syndromes associated with risk for PDAC and their implications for patients and their relatives. In addition, other biologically relevant pathways and environmental and lifestyle risk factors are discussed. Future work may focus on elucidating additional genetic, environmental, and lifestyle risk factors that may modify PDAC risk to continue to identify individuals at increased risk for PDAC who may benefit from surveillance and risk reducing interventions.

Health risk assessment of heavy metal pollutants in Iranian hen eggs: a systematic review and meta-analysis

Eggs are a high-quality, nutrient-dense source of protein that is available at a relatively low price and the contamination of eggs by heavy metals is an important issue in public health. This review aimed to assess the risk of heavy metal pollutants in Iranian hen eggs. Original full-text available studies in Iran, detecting levels of Pb, Cd, As, and Hg in whole or part of the egg, and published between January 2000 and March 2023 were selected based on the inclusion criteria. The random-effect model was used to estimate the pooled concentrations of Pb, Cd, As, and Hg in Iranian eggs in meta-analysis. The incremental lifetime cancer risk (ILCR) and the target hazard quotient (THQ) were estimated by both calculation and Monte Carlo simulations to determine the carcinogenic and non-carcinogenic risk of egg consumption, respectively. The pooled concentrations of heavy metals in Iranian hen eggs from nine articles (11 datasets: 10 studies on Pb, 7 on Cd, and 5 on As and Hg concentrations) were Pb 0.29 (95% CI 0.20-0.39) mg kg-1, Cd 0.04 (95% CI 0.03-0.06) mg kg-1, As 0.05 (95% CI 0.03-0.07) mg kg-1, and Hg 0.03 (95% CI 0.02-0.04) mg kg-1. THQ did not show the non-carcinogenic risk; however, the ILCR for Pb concentration showed the threshold carcinogenic risk (mean ILCR = 8.94e - 4 and 9.0E - 4 by calculation and Monte Carlo simulations, respectively), with the greater risk for Cd (mean ILCR = 2.02e - 2). The carcinogenic risk of Pb and Cd concentration in Iranian hen eggs shows the urgent need for programs and policies to lower the risk for consumers by providing healthier feeding.

Ginsenoside Rg5 as an anticancer drug: a comprehensive review on mechanisms, structure-activity relationship, and prospects for clinical advancement

Cancer remains one of the leading causes of death in the world. Despite the considerable success of conventional treatment strategies, the incidence and mortality rates are still high, making developing new effective anticancer therapies an urgent priority. Ginsenoside Rg5 (Rg5) is a minor ginsenoside constituent obtained exclusively from ginseng species and is known for its broad spectrum of pharmacological activities. This article aimed to comprehensively review the anticancer properties of Rg5, focusing on action mechanisms, structure-activity relationship (SAR), and pharmacokinetics attributes. The in vitro and in vivo activities of Rg5 have been proven against several cancer types, such as breast, liver, lung, bone, and gastrointestinal (GI) cancers. The modulation of multiple signaling pathways critical for cancer growth and survival mediates these activities. Nevertheless, human clinical studies of Rg5 have not been addressed before, and there is still considerable ambiguity regarding its pharmacokinetics properties. In addition, a significant shortage in the structure-activity relationship (SAR) of Rg5 has been identified. Therefore, future efforts should focus on further optimization by performing extensive SAR studies to uncover the structural features essential for the potent anticancer activity of Rg5. Thus, this review highlights the value of Rg5 as a potential anticancer drug candidate and identifies the research areas requiring more investigation.

The Role of Endocrine Disruption Chemical-Regulated Aryl Hydrocarbon Receptor Activity in the Pathogenesis of Pancreatic Diseases and Cancer

The aryl hydrocarbon receptor (AHR) serves as a ligand-activated transcription factor crucial for regulating fundamental cellular and molecular processes, such as xenobiotic metabolism, immune responses, and cancer development. Notably, a spectrum of endocrine-disrupting chemicals (EDCs) act as agonists or antagonists of AHR, leading to the dysregulation of pivotal cellular and molecular processes and endocrine system disruption. Accumulating evidence suggests a correlation between EDC exposure and the onset of diverse pancreatic diseases, including diabetes, pancreatitis, and pancreatic cancer. Despite this association, the mechanistic role of AHR as a linchpin molecule in EDC exposure-related pathogenesis of pancreatic diseases and cancer remains unexplored. This review comprehensively examines the involvement of AHR in EDC exposure-mediated regulation of pancreatic pathogenesis, emphasizing AHR as a potential therapeutic target for the pathogenesis of pancreatic diseases and cancer.

Human Health Effects of Oral Exposure to Chromium: A Systematic Review of the Epidemiological Evidence

The toxicity and carcinogenicity of hexavalent chromium via the inhalation route is well established. However, a scientific debate has arisen about the potential effects of oral exposure to chromium on human health. Epidemiological studies evaluating the connection between ingested chromium and adverse health effects on the general population are limited. In recent years, a wealth of biomonitoring studies has emerged evaluating the associations between chromium levels in body fluids and tissues and health outcomes. This systematic review brings together epidemiological and biomonitoring evidence published over the past decade on the health effects of the general population related to oral exposure to chromium. In total, 65 studies were reviewed. There appears to be an inverse association between prenatal chromium exposure and normal fetal development. In adults, parameters of oxidative stress and biochemical alterations increase in response to chromium exposure, while effects on normal renal function are conflicting. Risks of urothelial carcinomas cannot be overlooked. However, findings regarding internal chromium concentrations and abnormalities in various tissues and systems are, in most cases, controversial. Environmental monitoring together with large cohort studies and biomonitoring with multiple biomarkers could fill the scientific gap.

Microbiological and Molecular Study of Paranasal Sinus Infections of Children with Malignancy and Unknown Origin Fever in Markazi Province, Iran

Background

Children with malignancies are vulnerable to various infections, including sinus infections. Sinusitis is primarily caused by bacterial infections, followed by fungal infections. Due to this, evaluating the occurrence, diversity, and antibiotic susceptibility patterns of bacterial species that cause paranasal sinus infections in children with malignancy and unexplained fever is important.

Objective

To investigate the bacterial species accountable for sinusitis in children with malignancy and unexplained fever, and determine their susceptibility to antibiotics.

Methods

The study involved collecting 90 sinus samples from children aged 5 to 15 years with malignancy in Arak City, Iran. The isolates were identified using a combination of phenotypic, biochemical, and molecular techniques, including specific polymerase chain reaction and 16S ribosomal RNA gene sequencing. Drug susceptibility testing was performed following the Clinical & Laboratory Standards Institute 2021 guidelines.

Results

A total of 36 isolates (40%) were obtained, including 4 isolates of Nocardia (11.12%), 4 isolates of Escherichia coli (11.12%), 3 isolates of Klebsiella pneumoniae (8.33%), 5 isolates of Pseudomonas aeruginosa (13.88%), 3 isolates of Acinetobacter baumannii (8.33%), 4 isolates of Staphylococcus aureus (11.12%), 3 isolates of Staphylococcus epidermidis (8.33%), 5 isolates of Streptococcus agalactiae (13.88%), 2 isolates of Streptococcus pneumoniae (5.55%), and 3 isolates of Enterococcus faecium (8.33%). The isolates showed the most sensitivity to imipenem and trimethoprim-sulfamethoxazole and the least sensitivity to erythromycin and tetracycline.

Conclusions

The findings of the study indicate that sinusitis can contribute to fever of unknown origin in patients with cancer. Therefore, it is recommended to use a combination of molecular and phenotypic methods for accurate identification of isolates. This approach can provide more reliable and precise results, leading to better diagnosis and treatment of sinusitis infections in children with malignancy.

A Review of the Efficacy of the Low Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAP) Diet in Managing Gastrointestinal Symptoms Related to Cancer Treatment

The low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet, designed to alleviate symptoms in individuals with irritable bowel syndrome (IBS), focuses on limiting the consumption of poorly absorbed fermentable carbohydrates known as FODMAP. These FODMAP are believed to be the primary triggers for food-related gastrointestinal symptoms in functional gastrointestinal disorders. However, there is currently insufficient direct evidence investigating the role of low FODMAP diets in cancer patients undergoing treatment. This review aims to summarize the current evidence on the low FODMAP diet and its potential implications for cancer patients in terms of treatment outcomes, alleviating gastrointestinal symptoms, and overall health. A systematic literature search was conducted using databases, including PubMed, Scopus, Google Scholar, Web of Science, and Cochrane. Five studies met the criteria for inclusion in the review, and these studies covered rectal toxicity during radiotherapy, gastrointestinal symptoms in colorectal cancer patients, acute gastrointestinal toxicity during pelvic external beam radiotherapy, symptoms in patients with radiation-induced enteropathy, and chronic gastrointestinal sequelae resulting from pelvic organ cancer treatment. The available evidence suggests that a low FODMAP diet may offer advantages in reducing rectal gas and volume during radiotherapy, alleviating diarrhea symptoms, reducing symptom deterioration, and improving quality of life. However, these studies highlight the need for large-scale randomized trials, long-term follow-up, and guidelines to establish the efficacy, safety, and implementation strategies of the low FODMAP diet in different cancer contexts and patient populations. While preliminary findings reported some possible benefits of a low FODMAP diet for certain cancer patients, rigorous studies with large sample sizes are needed to provide more robust evidence. Further research is warranted to optimize the utilization of this diet as an adjunctive intervention for managing gastrointestinal symptoms in this population.

Toxic Metal and Essential Element Concentrations in the Blood and Tissues of Pancreatic Ductal Adenocarcinoma Patients

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive lethal neoplasm, and it has an average 5-year survival rate of less than 10%. Although the factors that influence PDAC development remain unclear, exposure to toxic metals or the imbalance in essential elements may have a role in PDAC-associated metabolic pathways.

METHODS

This study determined the concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn in whole blood, cancer and non-cancer tissues of patients affected by PDAC, and compared them with levels in healthy controls using inductively coupled plasma mass spectrometry.

RESULTS

Results of the whole blood showed significantly higher levels of Cr, Cu and Cu/Zn ratio in PDAC patients compared to the controls. In addition, the concentrations of Cu, Se, Fe and Zn significantly increased in cancer tissue compared to the healthy counterparts.

CONCLUSIONS

This study revealed evidence of altered metal levels in the blood and pancreatic tissues of PDAC patients with respect to healthy controls. These changes may contribute to multiple mechanisms involved in metal-induced carcinogenesis, including oxidative stress, DNA damage, genetic alteration, decreased antioxidant barriers and inflammatory responses. Thus, the analysis of metals can be used in the diagnosis and monitoring of PDAC neoplasms.

The Variant Allele Frequency of CTLA-4 rs11571317 (-658 C/T) Polymorphism With Colorectal Cancer Susceptibility in the Saudi Population and Other Ethnic Groups

The single nucleotide polymorphisms (SNPs) in the promoter region of the cytotoxic T-lymphocyte antigen-4 (CTLA-4) gene are directly associated with the progression and onset of various human cancers. These SNPs are important prognostic biomarkers for the prediction and early onset of cancer risk. The variant frequency of the CTLA-4 rs11571317 (-658 C/T) polymorphism may be affecting the various ethnic groups differently. In the present study, the allelic frequency distribution of -658 C/T polymorphism was assessed in the population of Saudi Arabia and compared with other world populations. The data from different cancers were extracted from case-control studies in the various ethnic groups by using PubMed (MEDLINE) and similar web databases. The frequency of CTLA-4 rs11571317 (-658 C/T) variant allele (T) was observed to be 25.5% and different frequencies were found significant for India (p = 0.001), USA (p = 0.03), and China (p = 0.04), when the prevalence of Saudi Arabian population was compared to that of other population groups. The current finding reveals that there is a distinct pattern of CTLA-4 rs11571317 (-658 C/T) polymorphism variant allele in the populations of Saudi Arabia, may be because of the differences in ethnicity. The observed findings can help in the assessment of the risk for the population harboring the risk allele of rs11571317 (-658 C/T) SNP and toward their subsequent susceptibility to cancer.

Exposure of environmental trace elements in prostate cancer patients: A multiple metal analysis

Prostate cancer (PCa) is the second leading cause of cancer-related deaths among men. To elucidate the connection between trace elements (arsenic: As, cadmium: Cd, lead: Pb, chromium: Cr, and nickel: Ni) and the risk of PCa, we analyzed trace element levels in the serum, urine, and tissues of PCa patients, while also examining their smoking status. We correlated these levels with their smoking habits. Notably, levels of Cd (P ≤ 0.05) and As (P ≤ 0.01) were significantly higher in the tumor tissue than in adjacent tissues. No significant differences were observed in the levels of Pb, Cr and Ni. Additionally, urinary Cd levels in 70% and arsenic levels in 2.3% of the PCa cohort were markedly higher than the CDC-reported cutoff (Cd ≤ 0.185 μg/L & As ≤100 μg/L). None displayed elevated levels of urinary Pb, Cr, and Ni. Conversely, in serum samples, the concentration of arsenic exceeded the CDC-determined limit (As ≤1.0 μg/L) in 31.69% of PCa patients. However, only 7.04% of patients had higher serum Cd levels than the CDC standard values (Cd ≤ 0.315 μg/L), while all PCa patients exceeded the Cr CDC limit (Cr ≤ 0.16 μg/L) and the Ni CDC limit (Ni ≤ 0.2 μg/L). On the contrary, no significant differences were observed in serum Pb (Pb ≤ 35.0 μg/L). Our findings establish a positive link between Cd and arsenic tissue concentrations and the risk of PCa. Subsequent studies are essential to determine whether elevated trace element levels pose a risk for the development of prostate carcinogenesis. Interestingly, among the PCa cohort comprising smokers, notably higher Cd levels were observed only in tumor tissues (P ≤ 0.01) and urine (P ≤ 0.05) compared to other elements or in other specimens.

Epidemiology of pancreatic cancer: New version, new vision

Pancreatic cancer (PC) is a devastating malignancy with an extremely high mortality rate and poses significant challenges to healthcare systems worldwide. The prevalence of PC risk factors spiked over the years, leading to a global increase in PC incidence rates. The contribution of different risk factors, however, varied from region to region due to genetic predisposition, environmental, social, and political factors underlying disease prevalence in addition to public health strategies. This comprehensive review aims to provide a thorough analysis of the epidemiology of PC, discussing its incidence, risk factors, screening strategies and socioeconomic burden. We compiled a wide range of seminal studies as well as epidemiological investigations to serve this review as a comprehensive guide for researchers, healthcare professionals, and policymakers keen for a more profound understanding of PC epidemiology. This review highlights the essentiality of persistent research efforts, interdisciplinary collaboration, and public health initiatives to address the expanding burden of this malignancy.

Consumer health risk assessment of Arsenic and Mercury in hen eggs through Monte Carlo simulations

BACKGROUND

This study was conducted to assess the concentration of heavy metals (arsenic and mercury) and estimate the probability that consumption of hen egg products collected in Iran has carcinogenic or non-carcinogenic consequences.

METHODS

A total of eighty-four hen eggs from 21 major brands were randomly selected from among thirty local supermarkets in two seasons (winter (January) and summer (August) 2022). Arsenic (As) and Mercury (Hg) was determined by using ICP-MS. The human health risk assessment refers to the formulation of the USEPA standard focused on Estimated Daily Intake (EDI), International Lifetime Cancer Risk (ILCR), Target Hazard Quotient (THQ), and Monte Carlo simulation (MCS) as a probabilistic method. Data analysis was carried out using the statistical software SPSS. Differences in mean concentrations of As and Hg in two seasons were tested by paired t-test.

RESULTS

Over two seasons, the average As and Hg concentrations in hen eggs were 0.79 and 0.18 µg.kg^-1, respectively. Seasonal difference in As concentration (p = 0.451) was not significant, whereas that of Hg concentration (p < 0.001) was significant. The calculated value of EDI was 0.29 µg As/day and 0.06 µg Hg/day. The EWI in the maximum scenario of as level in hen eggs was estimated to be 8.71 µg As and 1.89 µg Hg/month for Iranian adults. THQ's mean for As and Hg in adults was determined to be 0.00385 and 0.00066, respectively. In addition, ILCRs by MCS for As were 4.35E-4.

CONCLUSION

In total, the result indicates that there was not a significant risk of developing cancer; the calculation of THQ was still below the accepted level of 1, indicating that there was no risk while, according to most regulatory programs (ILCR > 10^- 4) shows a threshold carcinogenic risk of arsenic through consuming in hen eggs. Therefore, policymakers need to be aware that it is prohibited to establish chicken farms in heavily polluted urban areas. It is essential to regularly conduct examinations to measure the presence of heavy metals in both ground waters used for agriculture and the feed provided to chickens. Additionally, it is advisable to focus on raising public awareness about the importance of maintaining a healthy diet.

Modifiable Pancreatic Ductal Adenocarcinoma (PDAC) Risk Factors

This study aims to summarize the modifiable risk factors for pancreatic ductal adenocarcinoma (PDAC) that have been known for a long time, as well as information from the most recent reports. As a cancer with a late diagnosis and poor prognosis, accurate analysis of PDAC risk factors is warranted. The incidence of this cancer continues to rise, and the five-year survival rate is the lowest with respect to other tumors. The influence of cigarette smoking, alcohol consumption, and chronic pancreatitis in increasing the risk of pancreatic ductal adenocarcinoma is continually being confirmed. There are also newly emerging reports relating to the impact of lifestyle, including physical activity, the gut and oral microbiome, and hepatotropic viruses. A precise understanding of PDAC risk factors can help to identify groups of high-risk patients, and this may contribute to population awareness and education as well as earlier diagnoses with possible better treatment outcomes.

Risk assessment of lead and cadmium concentrations in hen's eggs using Monte Carlo simulations

The hen egg is one of the main sources of cheap, great quality, and nutritious food. This study aimed at determining the level of lead (Pb) and cadmium (Cd) in hen eggs and at assessing the carcinogenic and non-carcinogenic risks caused by the consumption of hen eggs collected in Iran. A total of 42 hen eggs from 17 major brands were randomly sampled from supermarkets. Lead and cadmium concentrations were determined by using inductively coupled plasma mass spectrometry (ICP-MS). Additionally, using the Monte Carlo simulation (MCS) method to calculate dietary exposure, target hazard quotient (THQ), and incremental lifetime cancer risk (ILCR), the related human health risk associated with ingesting these hazardous metals for adults was evaluated. The average Pb and Cd concentrations in whole eggs were 7.16 ± 0.248, and 2.83 ± 0.151 μg kg^-1, respectively, which were less than the maximum permitted levels, established by FAO/WHO and the Institute of Standards and Industrial Research of Iran (ISIRI). Pb and Cd concentrations were significantly correlated at the 0.05 level (r = 0.350). Regarding the levels of Pb and Cd in eggs, overall, the estimated weekly intake (EWI) of these metals for adults by egg consumption was determined 0.014 and 0.007 mg/week, respectively, which were lower than the risk values suggested. The carcinogenic and non-carcinogenic indexes of Cd and Pb indicated that the adult population in Iran was safe (THQ Pb and Cd <1, ILCR <10^-6 Pb). It should be emphasized that this research primarily focuses on egg consumption, which may account for a relatively small portion of Iranian consumers' overall exposure to Pb and Cd. Therefore, a comprehensive study on the risk assessment of these metals through whole-diet foods is recommended. The findings showed that lead and cadmium levels in all evaluated eggs were suitable for human consumption. Adults' Pb and Cd exposure from eating eggs was significantly lower than the risk levels established by Joint FAO/WHO Expert Committee on Food Additives (JECFA), per the exposure assessment. According to the THQ values of these dangerous metals, which were below one value, egg eating by Iranian consumers does not present a non-carcinogenic risk. In addition, this finding provides accurate and reliable information for policymakers to improve food safety status to reduce public health hazards.

Toxic mechanisms of cadmium and exposure as a risk factor for oral and gastrointestinal carcinomas

Incidence and mortality rates of gastrointestinal (GI) and oral cancers are among the highest in the world, compared to other cancers. GI cancers include esophageal, gastric, colon, rectal, liver, and pancreatic cancers, with colorectal cancer being the most common. Oral cancer, which is included in the head and neck cancers category, is one of the most important causes of death in India. Cadmium (Cd) is a toxic element affecting humans and the environment, which has both natural and anthropogenic sources. Generally, water, soil, air, and food supplies are reported as some sources of Cd. It accumulates in organs, particularly in the kidneys and liver. Exposure to cadmium is associated with different types of health risks such as kidney dysfunction, cardiovascular disease, reproductive dysfunction, diabetes, cerebral infarction, and neurotoxic effects (Parkinson's disease (PD) and Alzheimer's disease (AD)). Exposure to Cd is also associated with various cancers, including lung, kidney, liver, stomach, hematopoietic system, gynecologic and breast cancer. In the present study, we have provided and summarized the association of Cd exposure with oral and GI cancers.

Association between residential exposure to petrochemical industrial complexes and pancreatic cancer: a systematic review and meta-analysis

Increased in the global demand-expansion of the petrochemical industry is a possible environmental risk factor pancreatic cancer among residents living close to petrochemical complexes. This meta-analysis aimed to estimate the pooled risk of pancreatic cancer among residents living near petrochemical industrial complexes. We systematically searched and reviewed published studies in six databases based on the inclusion criteria derived from the population, exposure, comparator, and outcomes framework (population: general population; exposure: residence near petrochemical industrial complexes/living in cities with petrochemical industrial complexes; comparators: residents living farther away from petrochemical industrial complexes/living in cities without petrochemical industrial complexes; outcome: pancreatic cancer). We identified seven studies, covering 1,605,568 residents. Pooled analysis showed a significantly higher risk of pancreatic cancer among residents living near petrochemical industrial complexes (relative risk [RR] = 1.31, 95% confidence interval [CI] = 1.21-1.42) than those living farther away from petrochemical industrial complexes. Such effect was higher in female residents (RR = 1.34, 95% CI = 1.18-1.53) than in male residents (RR = 1.26, 95% CI = 1.12-1.41). This study suggests that exposure to petrochemical industry-related activities should be recognized as a risk factor for pancreatic cancer among residents living near petrochemical industrial complexes.

An Ecologic Study of the Association between 1,3-Dichloropropene and Pancreatic Cancer

BACKGROUND

1,3-Dichloropropene (1,3-D) is a soil fumigant that is used to protect fruit, vegetable, field, tree, and vine crops from nematode infestation and soil borne diseases. It is a commonly use pesticide, is applied by either direct injection into the soil or drip irrigation and is highlight volatile. Though currently classified as "Suggestive Evidence of Carcinogenic Potential", the literature in animal-based studies has inconsistent results and there is limited research among a human population with one study only among the California population. The purpose of the current analysis is to conduct a state-level analysis of the association between 1,3-D and pancreatic cancer mortality.

METHODS

Data for this ecological study were derived from death certificate data (for pancreatic mortality) from 1999 to 2020 and United States Geologic Survey National Water-Quality Assessment project for years 1992-2016 (1,3-D use). A negative binomial regression adjusted for selected lifestyle risk factors of pancreatic cancer (i.e., obesity, alcohol use, and smoking prevalence) estimated rate ratios (RRs) and associated 95% confidence intervals (CIs)for the association between 1,3-D quartiles and pancreatic cancer mortality rate. Models lagged in five-year increments to account for the induction period of pancreatic cancer.

RESULTS

Overall, there was no association between 1,3-D quartile and pancreatic cancer mortality rate; however, limiting the analyses to states reporting 1,3-D use for at least 20 years, the highest quartile of 1,3-D use was associated with an 11% increase in the pancreatic cancer mortality rate in the five-year lagged model (RR 1.11, 95% CI 1.06-1.16). This association was consistent across the other lag periods.

CONCLUSIONS

Accounting for lifestyle factors associated with pancreatic cancer risk, there is a significantly increase rate of pancreatic cancer mortality among states that have the highest quartile of 1,3-D use and have been using 1,3-D for a long-term period.

Pesticides and pancreatic adenocarcinoma: A transversal epidemiological, environmental and mechanistic narrative review

Pancreatic adenocarcinoma (PA) incidence is rising worldwide, especially in France. The evolution of known risk factors such as tobacco smoking, obesity, type 2 diabetes, chronic pancreatitis, or constitutional mutations is not sufficient to explain this trend. Pesticides are known risk factors in other malignancies. Previous studies have outlined pesticides' influence in PA, such as dichlorodiphenyltrichloroethane as plausible risk factors. The general population is directly or indirectly exposed to pesticides through air, food or water. Some of these chemicals may accumulate in the body all along lifetime and may harm carriers. The toxic mixing effects of these chemicals are not well documented. Several hypotheses have been put forward to explain how pesticides can induce indirect (fatty pancreas, induced diabetes) or direct (oxidative stress, cell damage) carcinogenesis in pancreatic cells through inflammation. A strong corpus exists acknowledging pesticides as a PA risk factor. However, published studies do not provide a sufficient level of evidence to prove causality and current prospective case-control studies are still ongoing.

Tracking the Development of Cancer Care After 75 Years of Independence: India's Fight Against Cancer Since 1947

India is one of the fastest developing countries with tremendous growth in industrialization and healthcare facilities. Research and development in the field of healthcare improved the quality of life and well-being of our population. Despite the availability of healthcare facilities and infrastructure, we are still facing considerable challenges in the prevention, diagnosis, and treatment of cancer. The present review focuses on the history and development of cancer care facilities since independence. The advances in cancer diagnostics for early detection of cancer and developments in the field of conventional surgery, including laparoscopic and robotic surgeries, chemotherapy, and radiation therapy, are reviewed. Immunotherapy, vaccines, and selective targeting of tumor cells using nanotechnology are emerging areas in the field of cancer research.

Exocrine pancreatic cancer and living near to waste sites containing hazardous organic chemicals, New York State, USA - an 18-year population-based study

OBJECTIVES

The etiology of exocrine pancreatic cancer (EPC) remains unknown except for family history and smoking. Despite recent medical advances, rates of pancreatic cancer incidence and mortality are increasing. Although existing evidence suggests a potentially causal relationship between environmental chemical exposures and pancreatic cancer, whether residential exposure impacts pancreatic cancer rates remains unknown.

MATERIAL AND METHODS

The authors identified 28 941 patients diagnosed with exocrine pancreatic cancer in New York State exclusive of New York City for the years 1996-2013. Descriptive statistics and negative binomial regression were used in this ecological study to compare pancreatic cancer hospitalization rates among patients who lived in zip codes with hazardous waste sites (HWSs) containing persistent organic pollutants (POPs) and volatile organic pollutants (VOCs) compared with clean zip codes with no identified hazardous waste sites. The authors assessed the effect of selected known and suspected human carcinogens on the EPC hospitalization rates by subgroup analyses.

RESULTS

Compared with the clean sites, the pancreatic cancer hospital discharge rate in the "VOCs without POPs" and "VOCs and POPs" sites, after adjustment for potential confounders were 1.06 (95% CI: 1.03-1.09) and 1.05 (95% CI: 1.01-1.08), respectively. In the analysis by specific chemicals, rate ratios (RR) for the benzene (RR = 1.12) and ethylbenzene (RR = 1.34) in the non-chlorinated VOCs group, trichloroethylene (RR = 1.07) and tetrachloroethylene (RR = 1.11) in the chlorinated VOCs group, chlorinated pesticides (RR = 1.11) and PCBs (RR = 1.05) in the POPs groups were statistically significant (p-values <0.05) compared with clean sites.

CONCLUSIONS

Compared with the clean sites, the pancreatic cancer hospital discharge rate in the "VOCs without POPs" and "VOCs and POPs" sites, after adjustment for potential confounders were 1.06 (95% CI: 1.03-1.09) and 1.05 (95% CI: 1.01-1.08), respectively. In the analysis by specific chemicals, rate ratios (RR) for the benzene (RR = 1.12) and ethylbenzene (RR = 1.34) in the non-chlorinated VOCs group, trichloroethylene (RR = 1.07) and tetrachloroethylene (RR = 1.11) in the chlorinated VOCs group, chlorinated pesticides (RR = 1.11) and PCBs (RR = 1.05) in the POPs groups were statistically significant (p-values <0.05) compared with clean sites. Int J Occup Med Environ Health. 2022;35(4):459-71.

Proscillaridin A induces mitochondrial damage and autophagy in pancreatic cancer and reduces the stability of SMAD4 in Panc-1 cells

Background

Pancreatic cancer (PC) is a highly metastatic and lethal cancer with a very low overall 5-year survival rate. There is an urgent need for identifying new therapeutic agents for this deadly disease. Cardiac glycosides (CGs) have been traditionally used for their potent cardiovascular activities and have also recently been reported to exhibit anti-tumor effects. Proscillaridin A (Pro A), a natural CG, has been shown to display anti-tumor effects on multiple cancer types.

Methods

The cytotoxic effect of Pro A on PC cells was determined using cell viability assay, colony formation assay and transwell assay in vitro. Cell apoptosis, cell cycle, reactive oxygen species (ROS) generation, intracellular Ca²⁺ levels and mitochondrial membrane potential (MMP) were assayed by flow cytometry. Panc-1-xenografted mice model was used to evaluate Pro A’s effect in tumor growth. Mitochondria morphology was observed by transmission electron microscopy. LC3 aggregation was assessed by GFP-LC3 fluorescence microscopy. Gene expression was assayed by western blot or real-time quantitative polymerase chain reaction (qPCR).

Results

Pro A inhibits the proliferation, migration and invasion of Panc-1, BxPC-3 and AsPC-1 PC cells in vitro, and Panc-1 cells display the highest sensitivity with an IC50 at the nano-molar level. In vivo, Pro A treatment inhibits tumor progression in Panc-1 xenograft nude mice. Pro A treatment promotes both cell apoptosis and autophagy, and Pro A-treated PC cells display characteristics of mitochondrial damage including increased ROS generation, intracellular Ca²⁺ levels and disruption of MMP. In addition, high sensitivity towards Pro A of Panc-1 cells compared to BxPC-3 and AsPC-1 cells could be partially attributed to the loss of endogenous SMAD4 expression in the latter.

Conclusions

Our findings suggest that Pro A constitutes a promising therapeutic candidate for certain types of PC.

Modifiable and Non-Modifiable Risk Factors for the Development of Non-Hereditary Pancreatic Cancer

Pancreatic cancer is becoming an increasing healthcare concern. Though it is a 14th most common cancer worldwide, its incidence is steadily rising. Results of currently available therapies are still not satisfactory. Therefore, great attention should be put on the identification and reduction of risk factors for pancreatic cancer. A thorough up-to-date review of available data on the impact of well-established and novel risk factors of pancreatic cancer development have been performed. Several risk factors associated with lifestyle have significant impact on the risk of pancreatic cancer (i.e., smoking, obesity, alcohol consumption). Physicians should also be aware of the novel findings suggesting increasing role of microbiome, including viral and bacterial infections, in the development of pancreatic cancer. A growing body of evidence suggest also an increased risk during certain occupational exposures. In general, lifestyle seems to be a major contributor in the development of pancreatic cancer. Special attention should be given to individuals with a vicious cluster consisting of metabolic syndrome, tobacco smoking and alcohol consumption. Physicians should urge patients to comply to healthy diet, cessation of smoking and moderation of alcohol consumption, which may halve pancreatic cancer incidence. Further studies are warranted to explore the potential use of therapeutic approach on novel risk factors (e.g., microbiome).

Plasma concentrations of persistent organic pollutants and pancreatic cancer risk

BACKGROUND

Findings and limitations of previous studies on persistent organic pollutants (POPs) and pancreatic cancer risk support conducting further research in prospective cohorts.

METHODS

We conducted a prospective case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Participants were 513 pancreatic cancer cases and 1020 matched controls. Concentrations of 22 POPs were measured in plasma collected at baseline.

RESULTS

Some associations were observed at higher concentrations of p, p'-DDT, trans-nonachlor, β-hexachlorocyclohexane and the sum of six organochlorine pesticides and of 16 POPs. The odds ratio (OR) for the upper quartile of trans-nonachlor was 1.55 (95% confidence interval 1.06-2.26; P for trend = 0.025). Associations were stronger in the groups predefined as most valid (participants having fasted >6 h, with microscopic diagnostic confirmation, normal weight, and never smokers), and as most relevant (follow-up ≥10 years). Among participants having fasted >6 h, the ORs were relevant for 10 of 11 exposures. Higher ORs were also observed among cases with microscopic confirmation than in cases with a clinical diagnosis, and among normal-weight participants than in the rest of participants. Among participants with a follow-up ≥10 years, estimates were higher than in participants with a shorter follow-up (for trans-nonachlor: OR = 2.14, 1.01 to 4.53, P for trend = 0.035). Overall, trans-nonachlor, three PCBs and the two sums of POPs were the exposures most clearly associated with pancreatic cancer risk.

CONCLUSIONS

Individually or in combination, most of the 22 POPs analysed did not or only moderately increased the risk of pancreatic cancer.

Bee pollens as biological indicators: An ecological assessment of pollution in Northern Turkey via ICP-MS and XPS analyses

In this study, pollens were collected from 25 different locations of Northern Turkey to investigate pollution monitoring. Surface chemistry of pollen samples was characterized by X-ray photoelectron spectroscopy (XPS). Then the concentrations of certain elements (Li, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Ba, and Pb) in pollen samples were determined by inductively coupled plasma mass spectrometry (ICP-MS) for the evaluation of environmental pollution. The levels of elements were detected in the following ranges (minimum-maximum, mg/kg dry pollen): Li (0.18-0.39), Al (24.98-308.04), V (6.18-98.58), Cr (1.05-6.81), Mn (13.85-95.91), Fe (52.20-326.26), Co (0.15-0.34), Ni (1.66-10.79), Cu (8.61-19.01), Zn (20.47-70.02), As (1.22-2.65), Se (0.39-0.67), Cd (0.05-0.74), Ba (0.73-16.30), and Pb (0.00-0.26). It has been concluded that there is a correlation between the pollen samples with high heavy metal concentrations and traffic density as these regions are closer to the road in the northern region. It is exposed to pollution from various sources such as intensified urbanization and tourism activities carried out on land and sea; industrial activities are increasing rapidly due to the opportunities offered by the coastal areas, sea transportation, and agricultural, domestic, and industrial pollution coming from the inner regions through rivers and streams. In this sense, pollens can be used as potential bio-indicators for monitoring heavy metal pollution and gives an idea about how we can use them for future assessing purposes.

Nickel's Role in Pancreatic Ductal Adenocarcinoma: Potential Involvement of microRNAs

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancer types with a limited overall survival rate due to the asymptomatic progression of symptoms in metastatic stages of the malignancy and the lack of an early reliable diagnostic biomarker. MicroRNAs (miRs/miRNAs) are small (~18–24 nucleotides), endogenous, non-coding RNAs, which are closely linked to the development of numerous malignancies comprising PDAC. Recent studies have described the role of environmental pollutants such as nickel (Ni) in PDAC, but the mechanisms of Ni-mediated toxicity in cancer are still not completely understood. Specifically, Ni has been found to alter the expression and function of miRs in several malignancies, leading to changes in target gene expression. In this study, we found that levels of Ni were significantly higher in cancerous tissue, thus implicating Ni in pancreatic carcinogenesis. Hence, in vitro studies followed by using both normal and pancreatic tumor cell lines and increasing Ni concentration increased lethality. Comparing LC50 values, Ni-acetate groups demonstrated lower values needed than in NiCl₂ groups, suggesting greater Ni-acetate. Panc-10.05 cell line appeared the most sensitive to Ni compounds. Exposure to Ni-acetate resulted in an increased phospho-AKT, and decreased FOXO1 expression in Panc-10.05 cells, while NiCl₂ also increased PTEN expression in Panc-10.05 cells. Specifically, following NiCl₂ exposure to PDAC cells, the expression levels of miR-221 and miR-155 were significantly upregulated, while the expression levels of miR-126 were significantly decreased. Hence, our study has suggested pilot insights to indicate that the environmental pollutant Ni plays an important role in the progression of PDAC by promoting an association between miRs and Ni exposure during PDAC pathogenesis.

Association of heavy metals and trace elements in renal cell carcinoma: A case-controlled study

PURPOSE

Trace elements and/or heavy metals are important for various biological activities. However, excess amount of these elements is associated with a variety of diseases, including cancer. We aimed to analyse the alterations of trace elements levels in renal cell carcinoma (RCC) patients.

MATERIALS AND METHODS

In this observational study, patients with biopsy proven RCC were taken as study group while age- and sex-matched healthy volunteers were taken as control. Blood and urine samples were compared for Arsenic (As), Copper (Cu), Manganese (Mn), Selenium (Se), Cadmium (Cd), Lead (Pb) and Mercury (Hg) levels measured by inductively coupled plasma mass-spectroscopy. Serum glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) antioxidant enzymes and lipid peroxidation (LPO) levels were assessed to know the redox status between 2 groups.

RESULTS

A total of 76 RCC cases and 64 controls were recruited in the study. A significantly higher concentration of As, Cu, Mn, Cd, Pb and Hg were observed in the blood of RCC patients as compared to controls. However, blood Se level was significantly lower in RCC patients. In 33 (43.4%) patients, one or more heavy metals were higher in the blood above their permitted level as compared to 10 (15.6%) subjects in control group. RCC patients had a higher urinary Mn and Se levels compared to controls. A significantly lower GSH-Px (182.08 ± 132.91 vs. 236.95 ± 132.94, P = 0.04) and a higher LPO levels (26.02 ± 20.79 vs. 14.06 ± 8.44, P = 0.003) were noted in RCC patients than controls. SOD levels were comparable between two groups.

CONCLUSIONS

A significantly altered heavy metals concentration is noted in the blood and urine in RCC patients as compared to healthy controls. An associated lower levels of GSH-Px antioxidant enzyme and increased LPO in RCC patients signifies an imbalance in the redox status.

miRNAs in the Regulation of Cancer Immune Response: Effect of miRNAs on Cancer Immunotherapy

In the last few decades, carcinogenesis has been extensively explored and substantial research has identified immunogenic involvement in various types of cancers. As a result, immune checkpoint blockers and other immune-based therapies were developed as novel immunotherapeutic strategies. However, despite being a promising therapeutic option, immunotherapy has significant constraints such as a high cost of treatment, unpredictable toxicity, and clinical outcomes. miRNAs are non-coding, small RNAs actively involved in modulating the immune system's multiple signalling pathways by binding to the 3'-UTR of target genes. miRNAs possess a unique advantage in modulating multiple targets of either the same or different signalling pathways. Therefore, miRNA follows a 'one drug multiple target' hypothesis. Attempts are made to explore the therapeutic promise of miRNAs in cancer so that it can be transported from bench to bedside for successful immunotherapeutic results. Therefore, in the current manuscript, we discussed, in detail, the mechanism and role of miRNAs in different types of cancers relating to the immune system, its diagnostic and therapeutic aspect, the effect on immune escape, immune-checkpoint molecules, and the tumour microenvironment. We have also discussed the existing limitations, clinical success and the prospective use of miRNAs in cancer.

Engineering of a functional pancreatic acinus with reprogrammed cancer cells by induced PTF1a expression

A pancreatic acinus is a functional unit of the exocrine pancreas producing digest enzymes. Its pathobiology is crucial to pancreatic diseases including pancreatitis and pancreatic cancer, which can initiate from pancreatic acini. However, research on pancreatic acini has been significantly hampered due to the difficulty of culturing normal acinar cells in vitro. In this study, an in vitro model of the normal acinus, named pancreatic acinus-on-chip (PAC), is developed using reprogrammed pancreatic cancer cells. The developed model is a microfluidic platform with an epithelial duct and acinar sac geometry microfabricated by a newly developed two-step controlled "viscous-fingering" technique. In this model, human pancreatic cancer cells, Panc-1, reprogrammed to revert to the normal state upon induction of PTF1a gene expression, are cultured. Bioinformatic analyses suggest that, upon induced PTF1a expression, Panc-1 cells transition into a more normal and differentiated acinar phenotype. The microanatomy and exocrine functions of the model are characterized to confirm the normal acinus phenotypes. The developed model provides a new and reliable testbed to study the initiation and progression of pancreatic cancers.

Pancreatic cancer epidemiology: understanding the role of lifestyle and inherited risk factors

Pancreatic cancer is a leading cause of cancer death worldwide and its global burden has more than doubled over the past 25 years. The highest incidence regions for pancreatic cancer include North America, Europe and Australia, and although much of this increase is due to ageing worldwide populations, there are key modifiable risk factors for pancreatic cancer such as cigarette smoking, obesity, diabetes and alcohol intake. The prevalence of these risk factors is increasing in many global regions, resulting in increasing age-adjusted incidence rates for pancreatic cancer, but the relative contribution from these risk factors varies globally due to variation in the underlying prevalence and prevention strategies. Inherited genetic factors, although not directly modifiable, are an important component of pancreatic cancer risk, and include pathogenic variants in hereditary cancer genes, genes associated with hereditary pancreatitis, as well as common variants identified in genome-wide association studies. Identification of the genetic changes that underlie pancreatic cancer not only provides insight into the aetiology of this cancer but also provides an opportunity to guide early detection strategies. The goal of this Review is to provide an up-to-date overview of the established modifiable and inherited risk factors for pancreatic cancer.

Curing pancreatic cancer

The distinct biology of pancreatic cancer with aggressive and early invasive tumor cells, a tumor promoting microenvironment, late diagnosis, and high therapy resistance poses major challenges on clinicians, researchers, and patients. In current clinical practice, a curative approach for pancreatic cancer can only be offered to a minority of patients and even for those patients, the long-term outcome is grim. This bitter combination will eventually let pancreatic cancer rise to the second leading cause of cancer-related mortalities. With surgery being the only curative option, complete tumor resection still remains the center of pancreatic cancer treatment. In recent years, new developments in neoadjuvant and adjuvant treatment have emerged. Together with improved perioperative care including complication management, an increasing number of patients have become eligible for tumor resection. Basic research aims to further increase these numbers by new methods of early detection, better tumor modelling and personalized treatment options. This review aims to summarize the current knowledge on clinical and biologic features, surgical and non-surgical treatment options, and the improved collaboration of clinicians and basic researchers in pancreatic cancer that will hopefully result in more successful ways of curing pancreatic cancer.

Associations between exposure to heavy metals and the risk of chronic kidney disease: a systematic review and meta-analysis

We performed a systematic review and meta-analysis to examine the relationship between heavy metals (HMs) exposure and the risk of chronic kidney disease (CKD). Databases of Web of Science, Embase, MEDLINE, and Scopus were searched through June 2020 to identify studies assessing the relationships between exposure to HMs (i.e. cadmium, lead, arsenic, mercury) and the risk of CKD, evaluated by decreased estimated glomerular filtration rate (eGFR) and/or increased proteinuria risks in adults (≥18 years). Data were pooled by random-effects models and expressed as weighted mean differences and 95% confidence intervals. The risk of bias was assessed by the Newcastle-Ottawa scale (NOS). Twenty-eight eligible articles (n = 107,539 participants) were included. Unlike eGFR risk (p = 0.10), Cadmium exposure was associated with an increased proteinuria risk (OR = 1.35; 95% CI: 1.13, 1.61; p < 0.001; I² = 79.7%). Lead exposure was associated with decreased eGFR (OR = 1.12; 95%CI: 1.03, 1.22; p = 0.008; I² = 87.8%) and increased proteinuria (OR = 1.25; 95% CI: 1.04, 1.49; p = 0.02; I² = 79.6) risks. Further, arsenic exposure was linked to a decreased eGFR risk (OR = 1.55; 95% CI: 1.05, 2.28; p = 0.03; I² = 89.1%) in contrast to mercury exposure (p = 0.89). Only two studies reported the link between arsenic exposure and proteinuria risk, while no study reported the link between mercury exposure and proteinuria risk. Exposure to cadmium, lead, and arsenic may increase CKD risk in adults, albeit studies were heterogeneous, warranting further investigations. Our observations support the consideration of these associations for preventative, diagnostic, monitoring, and management practices of CKD.

Association between heavy metals and colon cancer: an ecological study based on geographical information systems in North-Eastern Iran

Background

Colorectal cancer has increased in Middle Eastern countries and exposure to environmental pollutants such as heavy metals has been implicated. However, data linking them to this disease are generally lacking. This study aimed to explore the spatial pattern of age-standardized incidence rate (ASR) of colon cancer and its potential association with the exposure level of the amount of heavy metals existing in rice produced in north-eastern Iran.

Methods

Cancer data were drawn from the Iranian population-based cancer registry of Golestan Province, north-eastern Iran. Samples of 69 rice milling factories were analysed for the concentration levels of cadmium, nickel, cobalt, copper, selenium, lead and zinc. The inverse distance weighting (IDW) algorithm was used to interpolate the concentration of this kind of heavy metals on the surface of the study area. Exploratory regression analysis was conducted to build ordinary least squares (OLS) models including every possible combination of the candidate explanatory variables and chose the most useful ones to show the association between heavy metals and the ASR of colon cancer.

Results

The highest concentrations of heavy metals were found in the central part of the province and particularly counties with higher amount of cobalt were shown to be associated with higher ASR of men with colon cancer. In contrast, selenium concentrations were higher in areas with lower ASR of colon cancer in men. A significant regression equation for men with colon cancer was found (F(4,137) = 38.304, P < .000) with an adjusted R² of 0.77. The predicted ASR of men colon cancer was − 58.36 with the coefficients for cobalt = 120.33; cadmium = 80.60; selenium = − 6.07; nickel = − 3.09; and zinc = − 0.41. The association of copper and lead with colon cancer in men was not significant. We did not find a significant outcome for colon cancer in women.

Conclusion

Increased amounts of heavy metals in consumed rice may impact colon cancer incidence, both positively and negatively. While there were indications of an association between high cobalt concentrations and an increased risk for colon cancer, we found that high selenium concentrations might instead decrease the risk. Further investigations are needed to clarify if there are ecological or other reasons for these discrepancies. Regular monitoring of the amount of heavy metals in consumed rice is recommended.

Pancreatic Cancer Exposome Profile to Aid Early Detection and Inform Prevention Strategies

Pancreatic cancer (PCa) is associated with a poor prognosis and high mortality rate. The causes of PCa are not fully elucidated yet, although certain exposome factors have been identified. The exposome is defined as the sum of all environmental factors influencing the occurrence of a disease during a life span. The development of an exposome approach for PCa has the potential to discover new disease-associated factors to better understand the carcinogenesis of PCa and help with early detection strategies. Our systematic review of the literature identified several exposome factors that have been associated with PCa alone and in combination with other exposures. A potential inflammatory signature has been observed among the interaction of several exposures (i.e., smoking, alcohol consumption, diabetes mellitus, obesity, and inflammatory markers) that further increases the incidence and progression of PCa. A large number of exposures have been identified such as genetic, hormonal, microorganism infections and immune responses that warrant further investigation. Future early detection strategies should utilize this information to assess individuals' risk for PCa.

Stratification of population in NHANES 2009-2014 based on exposure pattern of lead, cadmium, mercury, and arsenic and their association with cardiovascular, renal and respiratory outcomes

BACKGROUND

Environmental exposure to toxic metals is an important risk factor to human health. Traditional methods have examined associations between a health endpoint and exposure to heavy metals by either univariate or multiple regression. In the setting of ubiquitous heterogeneous environmental exposures, statistical methods that incorporate mixed exposures are increasingly relevant and may provide new insight into the association between metal exposure and important cardiovascular, renal and respiratory outcomes.

OBJECTIVE

The objective of this study was to classify the population of National Health and Nutrition Examination Survey (NHANES) into different exposure subgroups using modern unsupervised clustering methods based on lead, cadmium, mercury, and arsenic measured in urine or whole blood, and to assess the association between the identified exposure groups and twelve important health endpoints.

METHODS

We analyzed a sub-cohort of 9662 subjects participating in the 6 cycles (2003-2004 to 2013-2014) of NHANES study. The urine levels of 3 heavy metals (total arsenic, lead, cadmium) and blood levels of 3 heavy metals (lead, cadmium and mercury) were analyzed using a two-step approach. In the first step, we stratified the population into subgroups using unsupervised clustering (k-medoids) based on levels of metals either in urine or in blood. Then, we examine the association between 12 health endpoints and identified exposure subgroups while controlling for age, sex, race/ethnicity, education, smoking status, BMI, and urinary creatinine.

RESULTS

The k-medoids algorithm clustered NHANES population into 2 groups based on either blood or urinary levels of heavy metals. The concentrations of all the three heavy metals were significantly different between the identified groups in blood (p < 2.2e-16) or in urine (p = 0). The group with higher concentrations was defined as the "high-exposure" group, while the group with lower concentrations was defined as "low-exposure" group. Association analysis with health outcomes suggested that the high-exposure group according to either blood or urinary metal levels had significantly higher total mortality (1.63-1.64 times higher, p < 0.0001), mortality caused by malignant neoplasms (2.05-2.62 times higher, p < 0.0002), Gamma-glutamyl transferase (GGT) (1.03-1.05 times higher, p < 0.0001). In addition, the high-exposure group based on blood levels was also significantly associated with SBP, death related to hypertension, heart disease and chronic lower respiratory disease, while the high-exposure group based on urinary concentrations had higher mortality related to nephritis.

CONCLUSIONS

We proposed an unsupervised clustering method to stratify the population into high- and low-exposure groups based on the co-exposure of heavy metals. The high-exposure groups, characterized by higher metal concentrations, had significant higher GGT, SBP, DBP, and mortality rates suggesting the detrimental effects of exposure to these heavy metals. The stratification of the NHANES population based on exposure patterns provides an informative method to study the impact of metal exposures on health outcomes.

Crude oil and public health issues in Niger Delta, Nigeria: Much ado about the inevitable

The importance of crude oil has come at a great cost. In many developing economies of the world, it can be described as the bitter-sweet crude for its double-edged impacts on the welfare, wellness and wellness of the people. Agitations and restiveness remain characteristic features of Niger Delta following claims of exploitation and neglect of the local population by the multinationals. Literature on the environmental and public health impacts of crude oil was searched from relevant databases such as google scholar, Science Direct, Scopus and PubMed. This paper is a translational scientific and toxicological insight on what should be done by the major players rather than casting unending aspersions. Since living near oil spills and crude oil production sites is an environmental stressor occasioned by exposure to both chemical pollutants and physical menace that are all detrimental to health, cumulative risk assessment CRA is proposed as a viable approach for a comprehensive understanding of the size of this problem. Multinational oil companies should support development of Environmental Medicine Research which will in turn generate data on both how to harness the natural resources to combat the public health issues associated with oil exploration and the mitigation and remediation of the environment. This endeavor will create a waste-to-wealth program that will pacify the restiveness in oil exploring communities. It will be interesting to know that in the same environment that breeds the elephant-in-the-parlor lies the natural antidotes to check-mate the public health malady.

A review of lifestyle and environment risk factors for pancreatic cancer

Pancreatic cancer (PaCa) is one of the deadliest cancers known and its incidence is increasing in the developed countries. Because of the lack of biomarkers that allow early detection and the tendency of the disease to be asymptomatic, the diagnosis comes often too late for effective surgical or chemotherapy intervention. Lifestyle factors, that may cause common genetic modifications occurring in the disease, interfere with pancreatic physiology or function, and play a role in PaCa development, have been of concern recently, since a strategy to prevent this severe cancer is needed. This review identifies the latest evidences related to increased risk of developing PaCa due to dietary habits such as high alcohol, fructose and red or processed meat intake, and pathological conditions such as diabetes, obesity and infections in addition to stress and smoking behaviour. It aims to highlight the importance of intervening on modifiable risk factors: the action on these factors could prevent a considerable number of new cases of PaCa.

On the impact of residential history in the spatial analysis of diseases with a long latency period: A study of mesothelioma in Belgium

Mesothelioma is a rare cancer caused by exposure to asbestos. Belgium has a known long history of asbestos production, resulting in one of the highest mesothelioma mortality rates worldwide. While the production of asbestos has stopped completely, the long latency period of mesothelioma, which can fluctuate between 20 and 40 years after exposure, causes incidences still to be frequent. Mesothelioma's long incubation time affects our assessment of its geographical distribution as well. Since patients' residential locations are likely to change a number of times throughout their lives, the location where the patients develop the disease is often far from the location where they were exposed to asbestos. Using the residential history of patients, we propose the use of a convolution multiple membership model (MMM), which includes both a spatial conditional autoregressive and an unstructured random effect. Pancreatic cancer patients are used as a control population, reflecting the population at risk for mesothelioma. Results show the impact of the residential mobility on the geographical risk estimation, as well as the importance of acknowledging the latency period of a disease. A simulation study was conducted to investigate the properties of the convolution MMM. The robustness of the results for the convolution MMM is assessed via a sensitivity analysis.

Influence of KRAS mutations, persistent organic pollutants, and trace elements on survival from pancreatic ductal adenocarcinoma

INTRODUCTION

Reasons why pancreatic ductal adenocarcinoma (PDAC) continues to have poor survival are only partly known. No previous studies have analyzed the combined influence of KRAS mutations, persistent organic pollutants (POPs), and trace elements upon survival in PDAC or in any other human cancer.

OBJECTIVE

To analyze the individual and combined influence of KRAS mutations, POPs, and trace elements upon survival from PDAC.

METHODS

Incident cases of PDAC (n = 185) were prospectively identified in five hospitals in Eastern Spain in 1992-1995 and interviewed face-to-face during hospital admission. KRAS mutational status was determined from tumour tissue through polymerase chain reaction and artificial restriction fragment length polymorphism. Blood and toenail samples were obtained before treatment. Serum concentrations of POPs were analyzed by high-resolution gas chromatography with electron-capture detection. Concentrations of 12 trace elements were determined in toenail samples by inductively coupled plasma mass spectrometry. Multivariable Cox proportional hazards regression was used to assess prognostic associations.

RESULTS

Patients with a KRAS mutated tumor had a 70% higher risk of early death than patients with a KRAS wild-type PDAC (hazard ratio [HR] = 1.7, p = 0.026), adjusting for age, sex, and tumor stage. KRAS mutational status was only modestly and not statistically significantly associated with survival when further adjusting by treatment or by treatment intention. The beneficial effects of treatment remained unaltered when KRAS mutational status was taken into account, and treatment did not appear to be less effective in the subgroup of patients with a KRAS mutated tumor. POPs did not materially influence survival: the adjusted HR of the highest POP tertiles was near unity for all POPs. When considering the joint effect on survival of POPs and KRAS, patients with KRAS mutated tumors had modest and nonsignificant HRs (most HRs around 1.3 to 1.4). Higher concentrations of lead, cadmium, arsenic, vanadium, and aluminium were associated with better survival. When KRAS status, POPs, and trace elements were simultaneously considered along with treatment, only the latter was statistically significantly related to survival.

CONCLUSIONS

In this study based on molecular, clinical, and environmental epidemiology, KRAS mutational status, POPs, and trace elements were not adversely related to PDAC survival when treatment was simultaneously considered; only treatment was independently related to survival. The lack of adverse prognostic effects of POPs and metals measured at the time of diagnosis provide scientific and clinical reassurance on the effects of such exposures upon survival of patients with PDAC. The weak association with KRAS mutations contributes to the scant knowledge on the clinical implications of a genetic alteration highly frequent in PDAC.

Regional Variation of Pancreatic Cancer Incidence in the Nile Delta Region of Egypt over a Twelve-Year Period

BACKGROUND

Pancreatic cancer is one of the deadliest forms of cancer, with incidence rates rising in many countries around the world. Geographic variation in pancreatic cancer incidence has not been studied extensively, especially in low- and middle-income countries. The aim of this study was to characterize the distribution of pancreatic cancer incidence in the central Nile Delta region of Egypt and to examine differences by urban and rural patient residence using the nation's only population-based cancer registry.

METHODS

Utilizing the Gharbiah province population-based cancer registry, data were abstracted for 1,089 pancreatic cancer cases diagnosed over twelve years from 1999 to 2010. Age- and sex-specific incidence rates were calculated and compared for urban and rural areas of the eight districts of Gharbiah.

RESULTS

Age-adjusted incidence of pancreatic cancer within Gharbiah varied considerably by urban/rural patient residence and by district. Incidence rates were 1.3 times higher in urban compared to rural areas (4.45 per 100,000 in urban areas and 3.43 per 100,000 in rural areas). The highest incidence rates were observed in urban centers of Kotour, El Santa, and Kafr El-Zayat districts (12.94, 8.32, and 7.89, respectively).

CONCLUSION

Incidence rates varied greatly by urban and rural areas and by district of residence in the Nile Delta region of Egypt. Future studies should examine potential environmental risk factors that may contribute to the geographic distribution of pancreatic cancer in this region.

Geraniol attenuates oxidative stress, bioaccumulation, serological and histopathological changes during aluminum chloride-hepatopancreatic toxicity in male Wistar rats

Aluminum chloride (AlCl₃) has different industrial applications including manufacturing paint and water treatment. The present study was designed to evaluate the alleviating effect of geraniol against AlCl₃-induced hepatopancreatic toxicity. To this end, forty male Wistar rats were divided into control (0.9% NaCl, IP), geraniol (100 mg/kg orally), AlCl₃ (70 mg/kg, IP), and AlCl₃ (70 mg/kg, IP) plus geraniol (100 mg/kg orally) groups and then were treated daily for 28 days. Based on the results, serum cholesterol, triglyceride, as well as liver and pancreas enzymes increased significantly (P < 0.05) while the level of insulin significantly decreased in AlCl₃-treated rats compared to the control group (P < 0.05). The presence of geraniol relieved the toxic effects of AlCl₃ as well. On the other hand, the level of malondialdehyde (MDA) increased in the AlCl₃-treated group while the activities of glutathione peroxidase and the total antioxidant activity demonstrated a reduction. However, the MDA level decreased while the antioxidant enzymes increased in co-treated with geraniol group. Histopathological examination revealed that simultaneous treatment with geraniol in AlCl₃ intoxicated rats ameliorate the liver lesions such as necrosis, inflammatory cell infiltration, vacuolar degeneration, along with hyperemia and the cell density of the Langerhans islands. Finally, the results indicated that geraniol attenuated the side effect of AlCl₃-induced hepatopancreatic toxicity.

Differential methylation landscape of pancreatic ductal adenocarcinoma and its precancerous lesions

BACKGROUND

Pancreatic cancer is one of the most lethal diseases with an incidence almost equal to the mortality. In addition to having genetic causes, cancer can also be considered an epigenetic disease. DNA methylation is the premier epigenetic modification and patterns of aberrant DNA methylation are recognized to be a common hallmark of human tumor. In the multistage carcinogenesis of pancreas starting from precancerous lesions to pancreatic ductal adenocarcinoma (PDAC), the epigenetic changes play a significant role.

DATA SOURCES

Relevant studies for this review were derived via an extensive literature search in PubMed via using various keywords such as pancreatic ductal adenocarcinoma, precancerous lesions, methylation profile, epigenetic biomarkers that are relevant directly or closely associated with the concerned area of our interest. The literature search was intensively done considering a time frame of 20 years (1998-2018).

RESULT

In this review we have highlighted the hypermethylation and hypomethylation of the precancerous PDAC lesions (pancreatic intra-epithelial neoplasia, intraductal papillary mucinous neoplasm, mucinous cystic neoplasm and chronic pancreatitis) and PDAC along with the potential biomarkers. We have also achieved the early epigenetic driver that leads to progression from precancerous lesions to PDAC. A bunch of epigenetic driver genes leads to progression of precancerous lesions to PDAC (ppENK, APC, p14/5/16/17, hMLH1 and MGMT) are also documented. We summarized the importance of these observations in therapeutics and diagnosis of PDAC hence identifying the potential use of epigenetic biomarkers in epigenetic targeted therapy. Epigenetic inactivation occurs by hypermethylation of CpG islands in the promoter regions of tumor suppressor genes. We listed all hyper- and hypomethylation of CpG islands of several genes in PDAC including its precancerous lesions.

CONCLUSIONS

The concept of the review would help to understand their biological effects, and to determine whether they may be successfully combined with other epigenetic drugs. However, we need to continue our research to develop more specific DNA-demethylating agents, which are the targets for hypermethylated CpG methylation sites.

A systematic review and meta-analysis of lead and cadmium concentrations in cow milk in Iran and human health risk assessment

The aim of the current research was to systematically review and summarize the studies that evaluated the concentration of lead (Pb) and cadmium (Cd) in cow milk in different regions of Iran and to perform a meta-analysis of the findings. Moreover, the non-carcinogenic and carcinogenic risks of Pb and Cd through milk consumption in adult and child consumers were assessed. As a result of a systematic search in the international and national databases between January 2008 and October 2018, 17 reports involving 1874 samples were incorporated in our study for meta-analysis. The pooled concentrations of Pb and Cd were estimated to be 13.95 μg mL^-1 (95% CI 9.72-18.11 μg mL^-1) and 3.55 μg mL^-1 (95% CI - 2.38-9.48 μg mL^-1), respectively, which were lower than the WHO/FAO and national standard limits. The estimated weekly intake (EWI) of Pb and Cd through consuming milk was 16.65 and 7 μg day^-1 for adults of 70 kg and 45 and 34 μg day^-1 for children of 26 kg, respectively, which was well below the risk values set by Joint FAO/WHO Expert Committee on Food Additives (JECFA). The maximum target hazard quotient values (THQs) of Pb and Cd were 5.55E-5 and 5.55E-5 for adults and 5.55E-5 and 5.55E-5 for children, respectively, which were lower than 1 value, suggesting that Iranian consumers are not exposed to non-carcinogenic risk through consuming milk. Moreover, the incremental lifetime cancer risk (ILCR) of Pb estimated to be 2.96E-04 in adults and 1.0E-03 in children, indicating that consumers in Iran are at threshold carcinogenic risk of Pb through consuming milk (ILCR > 10^-4). Therefore, planning and policy making for the sustainable reduction of these toxic metals in milk, particularly in industrial regions of Iran, are crucial.

Concentrations of trace elements and KRAS mutations in pancreatic ductal adenocarcinoma

Trace elements are a possible risk factor for pancreatic ductal adenocarcinoma (PDAC). However, their role in the occurrence and persistence of KRAS mutations remains unstudied. There appear to be no studies analyzing biomarkers of trace elements and KRAS mutations in any human cancer. We aimed to determine whether patients with KRAS mutated and nonmutated tumors exhibit differences in concentrations of trace elements. Incident cases of PDAC were prospectively identified in five hospitals in Spain. KRAS mutational status was determined through polymerase chain reaction from tumor tissue. Concentrations of 12 trace elements were determined in toenail samples by inductively coupled plasma mass spectrometry. Concentrations of trace elements were compared in 78 PDAC cases and 416 hospital-based controls (case-control analyses), and between 17 KRAS wild-type tumors and 61 KRAS mutated tumors (case-case analyses). Higher levels of iron, arsenic, and vanadium were associated with a statistically nonsignificant increased risk of a KRAS wild-type PDAC (OR for higher tertile of arsenic = 3.37, 95% CI 0.98-11.57). Lower levels of nickel and manganese were associated with a statistically significant higher risk of a KRAS mutated PDAC (OR for manganese = 0.34, 95% CI 0.14-0.80). Higher levels of selenium appeared protective for both mutated and KRAS wild-type PDAC. Higher levels of cadmium and lead were clear risk factors for both KRAS mutated and wild-type cases. This is the first study analyzing biomarkers of trace elements and KRAS mutations in any human cancer. Concentrations of trace elements differed markedly between PDAC cases with and without mutations in codon 12 of the KRAS oncogene, thus suggesting a role for trace elements in pancreatic and perhaps other cancers with such mutations. Environ. Mol. Mutagen., 60:693-703, 2019. © 2019 Wiley Periodicals, Inc.

Genotoxic, cytotoxic, and cytopathological effects in rats exposed for 18 months to a mixture of 13 chemicals in doses below NOAEL levels

The present study investigates the genotoxic and cytotoxic effects of long term exposure to low doses of a mixture consisting of methomyl, triadimefon, dimethoate, glyphosate, carbaryl, methyl parathion, aspartame, sodium benzoate, EDTA, ethylparaben, buthylparaben, bisphenol A and acacia gum in rats. Four groups of ten Sprangue Dawley rats (5 males and 5 females per group) were exposed for 18 months to the mixture in doses of 0xNOAEL, 0.0025xNOAEL, 0.01xNOAEL and 0.05xNOAEL (mg/kg bw/day). After 18 months of exposure, the rats were sacrificed and their organs were harvested. Micronuclei frequency was evaluated in bone marrow erythrocytes whereas the organs were cytopathologically examined by the touch preparation technique. The exposure to the mixture caused a genotoxic effect identified only in females. Cytopathological examination showed specific alterations of tissue organization in a tissue-type dependent manner. The observed effects were dose-dependent and correlated to various tissue parameters. Specifically, testes samples revealed degenerative and cellularity disorders, liver hepatocytes exhibited decreased glycogen deposition whereas degenerative changes were present in gastric cells. Lung tissue presented increased inflammatory cells infiltration and alveolar macrophages with enhanced phagocytic activity, whereas brain tissue exhibited changes in glial and astrocyte cells' numbers. In conclusion, exposure to very low doses of the tested mixture for 18 months induces genotoxic effects as well as monotonic cytotoxic effects in a tissue-dependent manner.

Target Elimination-Denatured and Unstable Proteins, Environmental Toxins, Metabolic Wastes, Immunosuppressive Factors and Chronic Inflammatory Factors of Medical System for Chronic Diseases Prevention and Health Promotion: A Narrative Review

BACKGROUND

The incidence of chronic diseases, such as cardiovascular disease, diabetes, overweight, obesity, cancer and other diseases has been increasing. It is a huge challenge to public health industry about how to provide risk intervention and preventive medical services and explore advanced technology platform for effective prevention and control of chronic diseases.

METHODS

We collaborated domestic and international experts on preventive medicine, and analyzed pathogenesis and risk factors for the major chronic diseases.

RESULTS

We established Target Elimination--denatured and unstable proteins, environmental toxins, metabolic wastes, immunosuppressive factors and chronic inflammatory factor (TE-PEMIC) system that offer us the standard and methods to eliminate and intervene pathogenic factors of the chronic diseases.

CONCLUSION

It provides new researches and exploring new ideas to prevent and intervene chronic diseases by applying the TE-PEMIC chronic diseases prevention medical technology system.

Toenail concentrations of trace elements and occupational history in pancreatic cancer

BACKGROUND

Some occupations potentially entailing exposure to cadmium, arsenic, lead, selenium, nickel, and chromium have been associated with an increased risk of exocrine pancreatic cancer (EPC), but no studies have assessed whether body concentrations of such compounds differed among subjects occupationally exposed and unexposed. No studies which found that exposure to such metals increased the risk of EPC assessed whether past occupations were the source of exposure.

OBJECTIVE

The aim was to analyse the relationship between toenail concentrations of trace elements and occupational history in EPC patients.

METHODS

The study included 114 EPC cases personally interviewed on occupational history and lifestyle factors. Occupations were coded according to the International Standard Classification of Occupations 1988. Selected occupational exposures were assessed by two industrial hygienists and with the Finnish job-exposure matrix (Finjem). Concentrations of 12 trace elements were determined in toenail samples by inductively coupled plasma mass spectrometry. Adjusted geometric means (aGMs) and 95% confidence intervals (95% CI) were calculated.

RESULTS

Patients occupationally exposed to aromatic hydrocarbon solvents (AHs) had higher concentrations of cadmium, manganese, lead, iron and vanadium. The aGM of cadmium concentrations for cases exposed to any pesticide was 0.056 μg/g [95% CI: 0.029-0.108], and, for unexposed cases, 0.023 μg/g [0.017-0.031]. Patients occupationally exposed to pesticides had higher concentrations of cadmium and manganese. Higher concentrations of vanadium, lead and arsenic were related to exposure to formaldehyde. Vanadium and lead were also associated with exposure to chlorinated hydrocarbon solvents, and arsenic was related to exposure to polycyclic aromatic hydrocarbons (PAHs).

CONCLUSIONS

Patients occupationally exposed to AHs, pesticides, chlorinated hydrocarbon solvents, formaldehyde, volatile sulphur compounds and PAHs had higher concentrations of several metals. These elements may account for some of the occupational risks previously reported for pancreatic cancer.

Risk of Different Cancers Among First-degree Relatives of Pancreatic Cancer Patients: Influence of Probands' Susceptibility Gene Mutation Status

BACKGROUND

Increased risk of malignancies other than pancreatic cancer (PC) has been reported among first-degree relatives (FDRs) of PC patients; however, the roles of susceptibility gene mutations are unclear. We assessed risk for 15 cancers among FDRs of unselected PC probands.

METHODS

Data on 17 162 FDRs, with more than 336 000 person-years at risk, identified through 2305 sequential PC probands enrolled at Mayo Clinic (2000-2016) were analyzed. Family history data were provided by the probands. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated, comparing malignancies observed among the FDRs with that expected using Surveillance, Epidemiology, and End Results (SEER) data. Genetic testing was performed among a subset of probands (n = 2094), enabling stratified analyses among FDRs based on whether the related proband tested positive or negative for inherited mutation in 22 sequenced cancer susceptibility genes. All statistical tests were two-sided.

RESULTS

Compared with SEER, PC risk was twofold higher among FDRs of PC probands (SIR = 2.04, 95% CI = 1.78 to 2.31, P < .001). Primary liver cancer risk was elevated among female FDRs (SIR = 2.10, 95% CI = 1.34 to 3.12, P < .001). PC risk was more elevated among FDRs of mutation-positive probands (SIR = 4.32, 95% CI = 3.10 to 5.86) than FDRs of mutation-negative probands (SIR = 1.77, 95% CI = 1.51 to 2.05, between-group P < .001). FDR PC risk was higher when the related proband was younger than age 60 years at diagnosis and mutation-positive (SIR = 5.24, 95% CI = 2.93 to 8.64) than when the proband was younger than age 60 years but mutation-negative (SIR = 1.76, 95% CI = 1.21 to 2.47, between-group P < .001). Breast (SIR = 1.29, 95% CI = 1.01 to 1.63) and ovarian (SIR = 2.38, 95% CI = 1.30 to 4.00) cancers were elevated among FDRs of mutation-positive probands.

CONCLUSIONS

Our study substantiates twofold risk of PC among FDRs of PC patients and suggests increased risk for primary liver cancer among female FDRs. FDRs of susceptibility mutation carriers had substantially increased risk for PC and increased risk for breast and ovarian cancers.

Methodological issues in a prospective study on plasma concentrations of persistent organic pollutants and pancreatic cancer risk within the EPIC cohort

BACKGROUND

The use of biomarkers of environmental exposure to explore new risk factors for pancreatic cancer presents clinical, logistic, and methodological challenges that are also relevant in research on other complex diseases.

OBJECTIVES

First, to summarize the main design features of a prospective case-control study -nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort- on plasma concentrations of persistent organic pollutants (POPs) and pancreatic cancer risk. And second, to assess the main methodological challenges posed by associations among characteristics and habits of study participants, fasting status, time from blood draw to cancer diagnosis, disease progression bias, basis of cancer diagnosis, and plasma concentrations of lipids and POPs. Results from etiologic analyses on POPs and pancreatic cancer risk, and other analyses, will be reported in future articles.

METHODS

Study subjects were 1533 participants (513 cases and 1020 controls matched by study centre, sex, age at blood collection, date and time of blood collection, and fasting status) enrolled between 1992 and 2000. Plasma concentrations of 22 POPs were measured by gas chromatography - triple quadrupole mass spectrometry (GC-MS/MS). To estimate the magnitude of the associations we calculated multivariate-adjusted odds ratios by unconditional logistic regression, and adjusted geometric means by General Linear Regression Models.

RESULTS

There were differences among countries in subjects' characteristics (as age, gender, smoking, lipid and POP concentrations), and in study characteristics (as time from blood collection to index date, year of last follow-up, length of follow-up, basis of cancer diagnosis, and fasting status). Adjusting for centre and time of blood collection, no factors were significantly associated with fasting status. Plasma concentrations of lipids were related to age, body mass index, fasting, country, and smoking. We detected and quantified 16 of the 22 POPs in more than 90% of individuals. All 22 POPs were detected in some participants, and the smallest number of POPs detected in one person was 15 (median, 19) with few differences by country. The highest concentrations were found for p,p'-DDE, PCBs 153 and 180 (median concentration: 3371, 1023, and 810 pg/mL, respectively). We assessed the possible occurrence of disease progression bias (DPB) in eight situations defined by lipid and POP measurements, on one hand, and by four factors: interval from blood draw to index date, tumour subsite, tumour stage, and grade of differentiation, on the other. In seven of the eight situations results supported the absence of DPB.

CONCLUSIONS

The coexistence of differences across study centres in some design features and participant characteristics is of relevance to other multicentre studies. Relationships among subjects' characteristics and among such characteristics and design features may play important roles in the forthcoming analyses on the association between plasma concentrations of POPs and pancreatic cancer risk.