Prediagnostic plasma concentrations of organochlorines and risk of B-cell non-Hodgkin lymphoma in envirogenomarkers: a nested case-control study

Molecular insights into PCB neurotoxicity: Comparing transcriptomic responses across dopaminergic neurons, population blood cells, and Parkinson's disease pathology

Parkinson's disease (PD) is a complex neurodegenerative disorder influenced by genetic factors and environmental exposures. Polychlorinated biphenyls (PCBs), a group of synthetic organic compounds, have been identified as potential environmental risk factors for neurodegenerative diseases, including PD. We explored PCB-induced neurotoxicity mechanisms using iPSC-derived dopaminergic neurons and assessed their transcriptomic responses to varying PCB concentrations (0.01 μM, 0.5 μM, and 10 μM). Specifically, we focused on PCB-180, a congener known for its accumulation in human brains. The exposure durations were 24 h and 74 h, allowing us to capture both short-term and more prolonged effects on gene expression patterns. We observed that PCB exposure led to the suppression of oxidative phosphorylation, synaptic function, and neurotransmitter release, implicating these pathways in PCB-induced neurotoxicity. In our comparative analysis, we noted similarities in PCB-induced changes with other PD-related compounds like MPP+ and rotenone. Our findings also aligned with gene expression changes in human blood derived from a population exposed to PCBs, highlighting broader inflammatory responses. Additionally, molecular patterns seen in iPSC-derived neurons were confirmed in postmortem PD brain tissues, validating our in vitro results. In conclusion, our study offers novel insights into the multifaceted impacts of PCB-induced perturbations on various cellular contexts relevant to PD. The use of iPSC-derived dopaminergic neurons allowed us to decipher intricate transcriptomic alterations, bridging the gap between in vitro and in vivo findings. This work underscores the potential role of PCB exposure in neurodegenerative diseases like PD, emphasizing the need to consider both systemic and cell specific effects.

Epidemiology and etiology of diffuse large B-cell lymphoma

As the most common non-Hodgkin lymphoma subtype, diffuse large B-cell lymphoma (DLBCL) incidence patterns generally parallel that for NHL overall. Globally, DLBCL accounts for a third of all NHLs, ranging between 20% and 50% by country. Based on United States (U.S.) cancer registry data, age-standardized incidence rate for DLBCL was 7.2 per 100,000. DLBCL incidence rises with age and is generally higher in males than females; in the U.S., incidence is highest among non-Hispanic whites (9.2/100,000). Like NHL incidence, DLBCL incidence rose in the first half of the 20th century but has largely plateaued. However, there is some evidence that incidence rates are rising in areas of historically low rates, such as Asia; there are also estimates for rising DLBCL incidence in the near future due to the changing demographics in developed countries whose aging population is growing. Established risk factors for DLBCL include those that result in severe immune deficiency such as HIV/AIDS, inherited immunodeficiency syndromes, and organ transplant recipients. Factors that lead to chronic immune dysregulations are also established risk factors, and include a number of autoimmune conditions (eg, Sjögren syndrome, systemic lupus erythematosus, rheumatoid arthritis), viral infections (eg, HIV, KSHV/HHV8, HCV, EBV), and obesity. Family history of NHL/DLBCL, personal history of cancer, and multiple genetic susceptibility loci are also well-established risk factors for DLBCL. There is strong evidence for multiple environmental exposures in DLBCL etiology, including exposure to trichloroethylene, benzene, and pesticides and herbicides, with recent associations noted with glyphosate. There is also strong evidence for associations with other viruses, such as HBV. Recent estimates suggest that obesity accounts for nearly a quarter of DLBCLs that develop, but despite recent gains in the understanding of DLBCL etiology, the majority of disease remain unexplained. An understanding of the host and environmental contributions to disease etiology, and concerted efforts to expand our understanding to multiple race/ethnic groups, will be essential for constructing clinically relevant risk prediction models and develop effective strategies for disease prevention.

PCB cause global DNA hypomethylation of human peripheral blood monocytes in vitro

We have recently reported significant associations between exposure to polychlorinated biphenyls (PCB) and alterations on genome-wide methylation of leukocyte DNA of healthy volunteers and provided evidence in support of an etiological link between the observed CpG methylation variations and chronic lymphocytic leukemia. The present study aimed to elucidate the effects of PCB in human lymphocytes' methylome in vitro. Therefore, U937 cells and human peripheral blood monocytes (PBMC) were exposed in vitro to the dioxin-like PCB-118, the non-dioxin-like PCB-153, and hexachlorobenzene (HCB) and thorough cytotoxicity, genotoxicity and global CpG methylation analyses were performed. All compounds currently tested did not show any consistent significant genotoxicity at all exposure periods and concentrations used. On the contrary, extensive dose-dependent hypomethylation was observed, even at low concentrations, in stimulated PBMC treated with PCB-118 and PCB-153 as well as a small but statistically significant hypomethylation in HCB-treated stimulated cells.

A systematic review and meta-analysis of occupational exposures and risk of follicular lymphoma

BACKGROUND

The etiology of follicular lymphoma (FL), a common non-Hodgkin lymphoma subtype, is largely unknown.

OBJECTIVE

We performed a systematic review and meta-analysis of observational studies examining the relationship between occupational exposures and FL risk.

METHODS

We searched Ovid MEDLINE, Ovid EMBASE, and Web of Science for eligible observational studies examining job titles or occupational exposures prior to January 1, 2020. We performed a narrative synthesis and used random-effects models to generate meta-estimates of relative risk (RR) with 95% confidence intervals (95%CI) for exposures reported by three or more studies.

RESULTS

Fifty-eight studies were eligible. Ten cohort and 37 case-control studies quantified FL risk in relation to any exposure to one or more occupational groups or agents. Eight cohort and 19 case-control studies examined dose-response relationships. We found evidence of a positive association with increasing plasma concentration of dichlorodiphenyldichloroethylene (DDE; meta-RR = 1.51, 95%CI = 0.99, 2.31; I² = 0.0%) and polychlorinated biphenyls (PCBs; meta-RR = 1.47, 95%CI = 0.97, 2.24; I² = 8.6%). We observed a positive association with exposure to any solvent (meta-RR = 1.16, 95%CI = 1.00, 1.34; I² = 0.0%) and chlorinated solvents (meta-RR = 1.35, 95%CI = 1.09, 1.68; I² = 0.0%). Single studies reported a significant positive dose-response association for exposure to any pesticide, hexachlorobenzene, any organophosphate, diazinon, metolachlor, carbaryl, lindane, trichloroethylene, oils/greases, and extremely low-frequency magnetic fields. Job title-only analyses suggested increased risk for medical doctors and spray painters, and decreased risk for bakers and teachers. Overall, studies demonstrated low risk of bias, but most studies examined small numbers of exposed cases.

CONCLUSIONS

Current evidence indicates a positive association between FL and occupational exposure to DDE, PCBs, any solvent and chlorinated solvents. Our findings may help guide policies and practices on the safe use of solvents and inform models of lymphomagenesis. Future studies with larger sample sizes and comprehensive quantitative exposure measures may elucidate other avoidable carcinogenic exposures.

Dietary exposure to polychlorinated biphenyls (PCB) and risk of Non-Hodgkin's lymphoma: Evidence from the French E3N prospective cohort

INTRODUCTION

Polychlorinated biphenyls (PCB) are persistent and bioaccumulative lipophilic substances, mostly used in the past by industry. Known to be cancerogenic, PCB are suspected to increase Non-Hodgkin's Lymphoma (NHL) risk in the general population mainly due to evidence from cases-controls studies. Since their interdiction in 1987, diet represents the main route of exposure for the general population, nevertheless no study has assessed the relationship between PCB dietary exposure and NHL risk. The aim of this study was to analyze the association between dietary exposures to dioxin like PCB (DL PCB) and non-dioxin like PCB (NDL PCB) and NHL risk in the E3N prospective cohort of French women.

MATERIALS AND METHODS

Among 67,879 women included in this study, 457 cases of NHL were confirmed during 21 years of follow-up. Dietary exposure to PCB was estimated combining food consumption data collected in E3N and food contamination data provided by French Agency for Food, Environmental and Occupational Health & Safety (ANSES) in the second French total diet study. Cox regression models, adjusted for potential confounders, were used to estimate hazard ratio (HR) and 95% confidence intervals (CI).

RESULTS

Average age at diagnosis was 67 years. The median dietary exposure to DL PCB and NDL PCB was, 18.5 pg TEQ/d and 138,843.2 pg/d, respectively. While no association was found between dietary exposure to DL PCB or NDL PCB and overall NHL risk, analyses by NHL histological subgroups showed a positive association between dietary exposures to DL PCB and Diffuse Large B Cell Lymphoma (OR3vs1 1.90, 95%CI [1.03-3.51], p_trend 0.02). Nevertheless these findings were no longer statistically significant when the models were adjusted for fish and dairy products consumption. In addition, an inverse association was found between dietary exposure to NDL PCB and the risk of follicular lymphoma (OR3vs1 0.46, 95%CI [0.24-0.87], p_trend 0.01).

CONCLUSION

This is the first study to evaluate the association between dietary exposure to DL and NDL PCB and the risk of NHL in a prospective cohort study. Overall, the findings suggest a lack of association between dietary exposure to DL or NDL PCB and NHL risk. Additional studies are needed to reproduce these findings.

Treatment of lymphomas via regulating the Signal transduction pathways by natural therapeutic approaches: A review

Lymphoma is a heterogeneous group of malignancies, which comprises 4.2 % of all new cancer cases and 3.3 % of all cancer deaths in 2019, globally. The dysregulation of immune system, certain bacterial or viral infections, autoimmune diseases, and immune suppression are associated with a high risk of lymphoma. Although several conventional strategies have improved during the past few decades, but their detrimental impacts remain an obstacle to be resolved. However, natural compounds are considered a good option in the treatment of lymphomas because of their easy accessibility, specific mode of action, high biodegradability, and cost-effectiveness. Vegetables, fruits, and beverages are the primary sources of natural active compounds. The present review investigated the activities of different natural medicinal compounds including curcumin, MK615, resveratrol, bromelain, EGCG, and Annonaceous acetogenins to treat lymphomas. Moreover, in vitro and in vivo studies, classification, risk factors, and diagnosis of lymphoma are also discussed in the present review. The accumulated data proposed that natural compounds regulate the signaling pathways at the level of cell proliferation, apoptosis, and cell cycle to exhibit anti-lymphoma activities both in-vivo and in-vitro studies and suggested that these active compounds could be a good therapeutic option in the treatment of different types of lymphomas.

Prediagnostic serum concentrations of organochlorine pesticides and non-Hodgkin lymphoma: A nested case-control study in the Norwegian Janus Serum Bank Cohort

BACKGROUND

Much of the marked increase in incidence of non-Hodgkin lymphoma (NHL) over the past few decades remains unexplained. Organochlorines, including organochlorine pesticides (OCPs), have been implicated as possible contributors to the increase, but the evidence is inconsistent.

OBJECTIVES

To investigate the relation between pre-diagnostic levels of OCPs and risk of NHL in a case-control study nested within the population-based Janus Serum Bank Cohort in Norway.

METHODS

Prediagnostic concentrations of 11 OCPs or OCP metabolites were measured in baseline blood samples collected between 1972 and 1978 from 190 cases and 190 controls matched on sex, county, age at blood draw, and date of blood draw. We conducted conditional logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for each quartile of lipid-corrected OCP/metabolite relative to the lowest quartile.

RESULTS

We observed non-significantly elevated ORs across quartiles of β-hexachlorocyclohexane compared to the lowest quartile (OR range: 1.40-1.82) although with no apparent monotonic exposure-response relationship. We also found an inverse association between risk of NHL and o,p'-DDT (OR for Q₄ vs. Q₁ = 0.44, 95% CI: 0.19, 1.01; p-trend = 0.05). In analyses stratified by age at blood collection and duration of follow-up, several other analytes, primarily chlordane-related compounds, showed inverse associations among younger participants or those with longer follow-up time between blood draw and NHL diagnosis.

CONCLUSIONS

We found only limited evidence of positive association between selected OCPs and development of NHL.

Serum levels of polychlorinated biphenyls and risk of non-Hodgkin lymphoma: A hospital-based case-control study

Polychlorinated biphenyls (PCB) have been classified by the International Agency for Research on Cancer (IARC) in Group 1 as carcinogenic to human, based on sufficient evidence in humans of an increased risk of cutaneous malignant melanoma and limited evidence for non-Hodgkin lymphoma (NHL). However present findings on the association of PCB exposure and NHL are still controversial. This study examined the relationship between PCB serum levels and risk of NHL in a Northern Italy area (Brescia province), where a chemical factory produced PCBs from 1938 to 1984, causing human contamination. A case-control study of 215 NHL patients and 215 control subjects was conducted. Cases and controls were assayed for serum levels of 33 PCB congeners. No associations were found between risk of NHL and serum levels of total PCBs (OR = 0.51; 95% CI: 0.25-1.04 for highest vs lowest quartile) or specific PCB congeners. The study confirmed a strong association of NHL with HCV infection (OR = 3.60; 95% CI: 1.30-10.02). This case-control study does not support the hypothesis of an association between current serum levels of PCBs and NHL development in the general population.

DNA methylation profiling implicates exposure to PCBs in the pathogenesis of B-cell chronic lymphocytic leukemia

OBJECTIVES

To characterize the impact of PCB exposure on DNA methylation in peripheral blood leucocytes and to evaluate the corresponding changes in relation to possible health effects, with a focus on B-cell lymphoma.

METHODS

We conducted an epigenome-wide association study on 611 adults free of diagnosed disease, living in Italy and Sweden, in whom we also measured plasma concentrations of 6 PCB congeners, DDE and hexachlorobenzene.

RESULTS

We identified 650 CpG sites whose methylation correlates strongly (FDR < 0.01) with plasma concentrations of at least one PCB congener. Stronger effects were observed in males and in Sweden. This epigenetic exposure profile shows extensive and highly statistically significant overlaps with published profiles associated with the risk of future B-cell chronic lymphocytic leukemia (CLL) as well as with clinical CLL (38 and 28 CpG sites, respectively). For all these sites, the methylation changes were in the same direction for increasing exposure and for higher disease risk or clinical disease status, suggesting an etiological link between exposure and CLL. Mediation analysis reinforced the suggestion of a causal link between exposure, changes in DNA methylation and disease. Disease connectivity analysis identified multiple additional diseases associated with differentially methylated genes, including melanoma for which an etiological link with PCB exposure is established, as well as developmental and neurological diseases for which there is corresponding epidemiological evidence. Differentially methylated genes include many homeobox genes, suggesting that PCBs target stem cells. Furthermore, numerous polycomb protein target genes were hypermethylated with increasing exposure, an effect known to constitute an early marker of carcinogenesis.

CONCLUSIONS

This study provides mechanistic evidence in support of a link between exposure to PCBs and the etiology of CLL and underlines the utility of omic profiling in the evaluation of the potential toxicity of environmental chemicals.

Serum organochlorines and non-Hodgkin lymphoma: A case-control study in Israeli Jews and Palestinians

Associations of organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs) with non-Hodgkin lymphoma are controversial. We compared serum levels of 6 OC pesticides and 38 PCBs in Israeli Jews (IJ) and Palestinian Arabs (PA) and assessed possible associations with B-cell non-Hodgkin lymphoma (B-NHL). Ninety B-NHL cases (50 IJ and 40 PA) and 120 controls (65 IJ and 55 PA) were included. Median concentrations of analytes in controls were compared across ethnic groups using quantile regression, adjusting for age and sex. We used logistic regression to derive odds ratios (OR) and 95% confidence intervals (CI) for detectable analytes and B-NHL, adjusting for age, ethnic group, faming and body mass index. Median values of PCBs and dichlorodiphenyldichloroethylene (DDE) were higher in IJ vs PA controls (P = 0.0007), as were several PCBs (74, 99, 118, 138, 146, 153, 156, 163, 170, and 180). Overall, OC pesticide and PCB exposures were comparable with reports from high-income countries. B-NHL was associated with PCB 146 (OR 1.70, 95% CI: 1.02, 2.83), PCB 156 (OR 1.75, 95% CI: 1.06, 2.89), and high-chlorinated PCBs (OR 1.55, 95% CI: 1.00, 2.40) in all study subjects. These associations were robust in quantile as well as sensitivity analyses. An association of DDE with B-NHL was noted in PA (OR 1.72, 95% CI: 1.07, 2.77), but not in IJ (OR 0.87, 95% CI: 0.59, 1.27). Although high-chlorinated PCB concentrations did not indicate high exposure levels, our findings indicate that B-NHL may be associated with this exposure.

Plasma levels of polychlorinated biphenyls and risk of cutaneous malignant melanoma: A hospital-based case-control study

Polychlorinated biphenyls (PCB) have been classified by the International Agency for Research on Cancer (IARC) in Group 1 as carcinogenic to human, based on sufficient evidence in humans of an increased risk of cutaneous malignant melanoma (CMM), however few studies have been done in the general population. This study examined the relationship between PCB plasma levels and risk of CMM adjusting for sun sensitivity and sun exposure in a province of Northern Italy (Brescia), where a chemical factory produced PCBs from 1938 to 1984 causing human contamination. A case-control study of 205 CMM patients and 205 control subjects was conducted. Cases and controls were assayed for plasma levels of 33 PCB congeners. No associations was found between risk of CMM and plasma levels of total PCB (OR = 0.81; 95% CI: 0.34-1.96 for highest vs lowest quartile) or specific congeners. The study confirmed the association with light skin colour (OR = 3.00; 95% CI: 1.91-4.73), cumulative lifetime UV exposure (OR = 2.56; 95% CI: 1.35-4.85) and high level of education (OR = 1.45; 95% CI: 1.03-2.05). This case-control study does not support the hypothesis of an association between current plasma levels of PCBs and CMM development in the general population.

Do polychlorinated biphenyls cause cancer? A systematic review and meta-analysis of epidemiological studies on risk of cutaneous melanoma and non-Hodgkin lymphoma

In 2015 a IARC Working Group upgraded the classification of PCBs to Group 1 "Carcinogenic to humans", also on the basis of evidence from epidemiological studies showing an excess risk for melanoma. Increased risks for non-Hodgkin lymphoma (NHL) and breast cancer were also reported though the evidence was limited. However, some recent reviews of studies on PCB exposure and risk of cancer provided discrepant findings. Therefore, we re-evaluated the association between exposure to PCBs and risk of melanoma and NHL by a systematic review and meta-analysis. We retrieved 11 independent cohort studies on occupationally exposed workers. About half of them showed increased standardized mortality or incidence ratios (SMRs or SIRs) for melanoma and none for NHL. The pooled SMRs were 1.32 (95% CI: 1.05-1.64) for melanoma and 0.94 (0.73-1.23) for NHL. Among population-based cohort and case-control studies with individual measures of PCB exposure, one only study was carried out on PCB exposure and melanoma, showing an odds ratio (OR) of 6.0 (2.0-18.2) for the highest compared to lowest quartile of PCB distribution. 13 cohort and case-control studies evaluated the association between NHL and PCB concentration in blood or subcutaneous fat, with summary OR = 1.5 (1.1-1.7) for the highest vs lowest quantile of PCB distribution. However, two cohort studies on people intoxicated by rice oil containing PCBs found no excess of deaths for skin cancer and inconsistent results for NHL. In conclusion, these findings do not provide a strong evidence that PCB exposure can increase the risk of melanoma and NHL in humans.

MicroRNA profile for health risk assessment: Environmental exposure to persistent organic pollutants strongly affects the human blood microRNA machinery

Persistent organic pollutants (POPs) are synthetic chemical substances that accumulate in our environment. POPs such as polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB) and dichlorodiphenyltrichloroethane (DDT) have been classified as carcinogenic to humans and animals. Due to their resistance to biodegradation humans are still exposed to these compounds worldwide. We aim to evaluate the miRNA and transcriptomic response of a human population exposed to POPs. The miRNA and transcriptomic response was measured in blood of healthy subjects by microarray technology and associated with the serum concentrations of six PCB congeners, DDE (a common DDT metabolite), and HCB. A total of 93 miRNA levels appeared significantly associated with the POP-exposure (FDR < 0.05). The miRNA profile includes four tumor suppressor miRNAs, namely miR-193a-3p, miR-152, miR-31-5p and miR-34a-5p. Integration of the miRNA profile with the transcriptome profile suggests an interaction with oncogenes such as MYC, CCND1, BCL2 and VEGFA. We have shown that exposure to POPs is associated with human miRNA and transcriptomic responses. The identified miRNAs and target genes are related to various types of cancer and involved in relevant signaling pathways like wnt and p53. Therefore, these miRNAs may have great potential to contribute to biomarker-based environmental health risk assessment.