In pancreatic ductal adenocarcinoma blood concentrations of some organochlorine compounds and coffee intake are independently associated with KRAS mutations

Derivatives of Plastics as Potential Carcinogenic Factors: The Current State of Knowledge

Simple Summary

Nowadays, micro- and nanoplastic particles can be found almost everywhere, being especially harmful for humans. Their absorption, primarily via inhalation and digestive routes, might lead to a particularly dangerous accumulation of those substances within the human body. Due to the alarming increase in contamination worldwide and excessive production of plastics and synthetic materials, there is an urgent need to investigate the effects of those substances on human health. So far, it has been observed that nano- and microplastics might be extremely harmful, leading to serious health conditions, such as cancers of various human body systems.

Abstract

Micro- and nanoplatics have been already reported to be potential carcinogenic/mutagenic substances that might cause DNA damage, leading to carcinogenesis. Thus, the effects of micro- and nanoplastics exposure on human health are currently being investigated extensively to establish clear relationships between those substances and health consequences. So far, it has been observed that there exists a definite correlation between exposure to micro- and nanoplastic particles and the onset of several cancers. Therefore, we have conducted research using PubMed, Web of Science, and Scopus databases, searching for all the research papers devoted to cancers that could be potentially related to the subject of exposure to nano- and microplastics. Ultimately, in this paper, we have discussed several cancers, including hepatocellular carcinoma, pancreatic cancer, pancreatic ductal adenocarcinoma, biliary tract cancer, and some endocrine-related cancers.

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.

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.

Tobacco Smoke and Ras Mutations Among Latino and Non-Latino Children with Acute Lymphoblastic Leukemia

BACKGROUND AND AIMS

Childhood acute lymphoblastic leukemia (ALL) is a biologically heterogeneous disease, and mutations in the KRAS and NRAS oncogenes are present at diagnosis in about one-fifth of cases. Ras mutations were previously associated with environmental exposures in leukemias as well as in many other cancer types. This study examined whether Ras mutation could define a unique etiologic group of childhood ALL associated with tobacco smoke, a well-established mutagen and carcinogen.

METHODS

We included 670 children with ALL enrolled in a case-control study in California (1995-2013), including 50.6% Latinos. Parental and child exposure to tobacco smoke was obtained from interviews. Sanger sequencing was used to detect the common KRAS and NRAS hotspot mutations in diagnostic bone marrow DNA. ALL cases were also characterized for common chromosome abnormalities. In case-case analyses, logistic regression analyses were used to estimate odds ratios to describe the association between tobacco smoke exposure and childhood ALL with Ras mutations.

RESULTS

KRAS or NRAS mutations were detected in ∼18% of children diagnosed with ALL. Ras mutations were more common among Latino cases compared with non-Latino whites and in high-hyperdiploid ALL. No associations were observed between parental smoking or child's passive exposure to smoke and Ras positive ALL.

CONCLUSIONS

The apparent lack of association between tobacco smoke and Ras mutation in childhood ALL suggests that Ras mutations do not specifically define a tobacco-related etiologic pathway. Reasons for racial and ethnic differences in ALL are not well understood and could reflect differences in etiology that warrant further examination.

Human contamination by persistent toxic substances: the rationale to improve exposure assessment

We know quite a lot about the generalized human contamination by environmental chemical agents; this statement is fully compatible with the view that most countries lack the necessary monitoring systems. We also know quite a lot about the toxic effects of environmental pollutants; this statement is fully compatible with the proposal that we need both more research and more energetic policies to decrease human contamination by such pollutants. Unsurprisingly, we know too little about the (environmental and social) causes and the etiopathogenesis (mechanisms) of the most prevalent diseases, and we will continue to miss relevant causes and mechanisms if we neglect the toxic chemicals that commonly contaminate humans, worldwide. Basic, clinical end environmental-epidemiological research on human health should more often consider integrating biomarkers of internal dose of environmental chemical pollutants. When we act in more responsible, rational, and scientific ways; when we become less dismissive towards environmental hazards; and when we thus neglect less the generalized human contamination by environmental chemical agents and their toxic effects, we will expand mechanistic biologic knowledge, and we shall as well increase the effectiveness of interventions and policies that enable the primary prevention of human diseases which cause huge amounts of economic burden and human suffering.

Fat, epigenome and pancreatic diseases. Interplay and common pathways from a toxic and obesogenic environment

The worldwide obesity epidemic is paralleled by a rise in the incidence of pancreatic disorders ranging from "fatty" pancreas to pancreatitis and cancer. Body fat accumulation and pancreatic dysfunctions have common pathways, mainly acting through insulin resistance and low-grade inflammation, frequently mediated by the epigenome. These mechanisms are affected by lifestyle and by the toxic effects of fat and pollutants. An early origin is common, starting in pediatric age or during the fetal life in response to nutritional factors, endocrine disruptor chemicals (EDCs) or parental exposure to toxics. A "fatty pancreas" is frequent in obese and is able to induce pancreatic damage. The fat is a target of EDCs and of the cytotoxic/mutagenic effects of heavy metals, and is the site of bioaccumulation of lipophilic and persistent pollutants related with insulin resistance and able to promote pancreatic cancer. Increased Body Mass Index (BMI) can act as independent risk factor for a more severe course of acute pancreatitis and obesity is also a well-known risk factor for pancreatic cancer, that is related with BMI, insulin resistance, and duration of exposure to the toxic effects of fat and/or of environmental pollutants. All these mechanisms involve gene-environment interactions through epigenetic factors, and might be manipulated by primary prevention measures. Further studies are needed, pointing to better assess the interplays of modifiable factors on both obesity and pancreatic diseases, and to verify the efficacy of primary prevention strategies involving lifestyle and environmental exposure to toxics.

Adjusting serum concentrations of organochlorine compounds by lipids and symptoms: a causal framework for the association with K-ras mutations in pancreatic cancer

In clinically aggressive diseases, patients experience pathophysiological changes that often alter concentrations of lipids and environmental lipophilic factors; such changes are related to disease signs and symptoms. The aim of the study was to compare the effects of correcting for total serum lipids (TSL) and other clinical factors on the odds of mutations in the K-ras oncogene by organochlorine compounds (OCs), in logistic models, in 103 patients with exocrine pancreatic cancer (EPC) using a causal directed acyclic graph (DAG) framework. Results and likelihood of bias were discussed in the light of possible causal scenarios. The odds of K-ras mutated EPC was associated with some TSL-corrected OCs, including p,p'-DDT (p-value: 0.008) and polychlorinated biphenyl 138 (p-trend: 0.024). When OCs were not corrected by TSL, the OR of a K-ras mutation was significant for p,p'-DDT (p-trend: 0.035). Additionally adjusting for cholestatic syndrome increased the ORs of TSL-corrected OCs. When models were adjusted by the interval from first symptom to blood extraction (ISE), the ORs increased for both TSL-corrected and uncorrected OCs. Models with TSL-corrected OCs and adjusted for cholestatic syndrome or ISE yielded the highest ORs. We show that DAGs clarify the covariates necessary to minimize bias, and demonstrate scenarios under which adjustment for TSL-corrected OCs and failure to adjust for symptoms or ISE may induce bias. Models with TSL-uncorrected OCs may be biased too, and adjusting by symptoms or ISE may not control such biases. Our findings may have implications as well for studying environmental causes of other clinically aggressive diseases.

Genome-wide association study identifies multiple susceptibility loci for pancreatic cancer

We performed a multistage genome-wide association study including 7,683 individuals with pancreatic cancer and 14,397 controls of European descent. Four new loci reached genome-wide significance: rs6971499 at 7q32.3 (LINC-PINT, per-allele odds ratio (OR) = 0.79, 95% confidence interval (CI) 0.74-0.84, P = 3.0 × 10(-12)), rs7190458 at 16q23.1 (BCAR1/CTRB1/CTRB2, OR = 1.46, 95% CI 1.30-1.65, P = 1.1 × 10(-10)), rs9581943 at 13q12.2 (PDX1, OR = 1.15, 95% CI 1.10-1.20, P = 2.4 × 10(-9)) and rs16986825 at 22q12.1 (ZNRF3, OR = 1.18, 95% CI 1.12-1.25, P = 1.2 × 10(-8)). We identified an independent signal in exon 2 of TERT at the established region 5p15.33 (rs2736098, OR = 0.80, 95% CI 0.76-0.85, P = 9.8 × 10(-14)). We also identified a locus at 8q24.21 (rs1561927, P = 1.3 × 10(-7)) that approached genome-wide significance located 455 kb telomeric of PVT1. Our study identified multiple new susceptibility alleles for pancreatic cancer that are worthy of follow-up studies.

Blood concentrations of persistent organic pollutants and prediabetes and diabetes in the general population of Catalonia

The aim was to analyze the effects of body mass index (BMI), low-dose exposure, mixtures of persistent organic pollutants (POPs), and lipid adjustment on the relationship between POP concentrations and diabetes and prediabetes in the general adult population of Catalonia (Spain). Serum concentrations of POPs were measured by gas chromatography with electron-capture detection in 886 participants in a health interview survey. The highest concentrations of all POPs analyzed were found in subjects who had diabetes. Levels were also higher in individuals with prediabetes than in subjects without the disorder. In models adjusted by age, sex and BMI, the prevalence of diabetes and prediabetes increased in a dose-dependent manner across quartiles of PCBs 118, 138, 153, and 180, and HCB. When models were further adjusted for lipids, the associations were slightly lower and statistically significant, the ORs for the upper quartile ranging from 2.0 to 2.8 (all p-values for linear trend <0.05). Concentrations of p,p'-DDT, p,p'-DDE and β-HCH were not associated with diabetes or prediabetes. Increasing concentrations of PCBs and HCB were positively associated with diabetes and prediabetes. Only part of the association was due to age and BMI. Findings support the hypothesis that exposure to POPs may be a diabetogenic factor in both obese and nonobese individuals.

Clinical validity of detecting K-ras mutations for the diagnosis of exocrine pancreatic cancer: a prospective study in a clinically-relevant spectrum of patients

The diagnostic utility of detecting K-ras mutations for the diagnosis of exocrine pancreatic cancer (EPC) has not been properly studied, and few reports have analysed a clinically relevant spectrum of patients. The objective was to evaluate the clinical validity of detecting K-ras mutations in the diagnosis of EPC in a large sample of clinically relevant patients. We prospectively identified 374 patients in whom one of the following diagnoses was suspected at hospital admission: EPC, chronic pancreatitis, pancreatic cysts, and cancer of the extrahepatic biliary system. Mutations in the K-ras oncogene were analysed by PCR and artificial RFLP in 212 patients. The sensitivity and specificity of the K-ras mutational status for the diagnosis of EPC were 77.7% (95% CI: 69.2-84.8) and 78.0% (68.1-86.0), respectively. The diagnostic accuracy was hardly modified by sex and age. In patients with either mutated K-ras or CEA > 5 ng/ml, the sensitivity and specificity were 81.0% (72.9-87.6) and 62.6% (72.9-87.6), respectively. In patients with mutated K-ras and CEA > 5 ng/ml the sensitivity was markedly reduced. In comparisons with a variety of non-EPC patient groups sensitivity and specificity were both always greater than 75%. In this clinically relevant sample of patients the sensitivity and specificity of K-ras mutations were not sufficiently high for independent diagnostic use. However, it seems premature to rule out the utility of K-ras analysis in conjunction with other genetic and 'omics' technologies.

The relative influence of diet and serum concentrations of organochlorine compounds on K-ras mutations in exocrine pancreatic cancer

BACKGROUND

In exocrine pancreatic cancer (EPC) mechanistic relationships may exist among some organochlorine compounds (OCs) and mutations in the K-ras oncogene, as well as among the latter and dietary factors.

OBJECTIVE

To analyze (1) the relationship between food intake and serum concentrations of OCs in EPC patients and (2) the relative influence of food and OCs on the frequency of K-ras mutations in EPC.

PATIENTS AND METHODS

Incident cases of EPC were prospectively identified, and interviewed face-to-face during hospital admission (N=135 patients with data on OCs and diet, and N=97 with additional information on K-ras status). OCs were measured by high-resolution gas chromatography with electron-capture detection.

RESULTS

Consumption of milk and other dairy products was positively associated with concentrations of p,p'-DDT, PCB 138 and PCB 153 (log-transformed betas=0.652, 0.588 and 0.317, respectively; all p<0.05). When adjusted by OCs, dairy products were no longer associated with K-ras. By contrast, after adjusting by consumption of dairy products, patients with the highest concentrations of p,p'-DDT and some PCBs remained more likely to have a K-ras-mutated EPC than patients with lower concentrations (OR for upper tertile of PCB 138=5.5, 95% CI: 1.3-23.4).

CONCLUSIONS

Dairy products were a source of OCs. The association between dairy products and K-ras mutations was not independent of OCs. By contrast, the association between OCs and K-ras was not confounded by dairy products. OCs may be more likely to contribute to the occurrence of K-ras mutations than nutrients contained in dairy products.