Breast Cancer and Exposure to Organochlorines in the CECILE Study: Associations with Plasma Levels Measured at the Time of Diagnosis and Estimated during Adolescence

Epigenetic Mechanisms of Endocrine-Disrupting Chemicals in Breast Cancer and Their Impact on Dietary Intake

Addressing the consequences of exposure to endocrine-disrupting chemicals (EDCs) demands thorough research and elucidation of the mechanism by which EDCs negatively impact women and lead to breast cancer (BC). Endocrine disruptors can affect major pathways through various means, including histone modifications, the erroneous expression of microRNA (miRNA), DNA methylation, and epigenetic modifications. However, it is still uncertain if the epigenetic modifications triggered by EDCs can help predict negative outcomes. Consequently, it is important to understand how different endocrine disrupters or signals interact with epigenetic modifications and regulate signalling mechanisms. This study proposes that the epigenome may be negatively impacted by several EDCs, such as cadmium, arsenic, lead, bisphenol A, phthalates, polychlorinated biphenyls and parabens, organochlorine, and dioxins. Further, this study also examines the impact of EDCs on lifestyle variables. In breast cancer research, it is essential to consider the potential impacts of EDC exposure and comprehend how EDCs function in tissues.

Biological concentrations of DDT metabolites and breast cancer risk: an updated systematic review and meta-analysis

The question of whether dichlorodiphenyltrichloroethane (DDT) exposure is related to breast cancer (BC) remains unanswered, possibly due to methodological constraints in the studies that have been performed. We aimed to update and synthesize the available epidemiological evidence on the relationship of p,p'-DDT, o,p'-DDT and p,p'-dichlorodiphenyldichloroethylene (p,p'- DDE) biological concentrations with female BC, focusing in methodological characteristics not addressed in previous reviews. We conducted an overview of reviews and a systematic review and meta-analysis. We used six databases and one search engine to identify meta-analyses based on systematic reviews, pooled analyses, and individual studies published from January 2000 to December 2021. For the overview of reviews, we assessed meta-analyses' risk of bias and carried out a narrative synthesis. For the meta-analysis, we estimated summary association measures with fixed or random effects models for each compound stratifying for characteristics of interest. We estimated a positive summary association between p,p'- DDT biological concentrations and BC in prospective studies (nested case control) with >10 years of follow-up (sOR=1.41; 95 %CI: 1.06-1.88). Among retrospective studies (hospital or population-based case-control), BC was positively related with p,p'-DDE biological concentrations (sOR=1.15; 95 %CI: 1.02-1.30), and with p,p'-DDT in women with mean serum concentrations>100 ng/g (sOR=1.33; 95 %CI: 1.25-1.41). Moreover, we detected a positive association between o,p'-DDT and BC (sOR=2.24; 95 %CI: 2.15-2.34). Our results support a positive relationship between DDT exposure and BC, and are useful to reinforce its worldwide prohibition, since this pesticide is still used in some countries, has long persistence in the human body and disseminates to other geographic areas.

Endocrine-disrupting chemicals and breast cancer: a meta-analysis

Background

Globally, the burden of breast cancer has increased significantly in recent decades. Emerging evidence suggested that endocrine-disrupting chemicals (EDCs), which have the potential to interfere with the function of normal hormones, may play a crucial role in this trend. However, the potential relationships were inconsistent in various studies.

Objective and search methods

In our study, we sought to fully evaluate the currently available epidemiological evidence to ascertain whether certain EDC congeners and their metabolites are related to breast cancer risk. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we conducted a comprehensive literature search of original peer-reviewed publications in three electronic databases: PubMed, Web of Science, and Embase. Publications that covered xenobiotic EDC exposures and breast cancer-confirmed histological results or antecedent medical records or reporting to health registers were taken into consideration.

Outcomes

The final result of the literature search was 6,498 references, out which we found 67 publications that matched the requirements for meta-analysis and eight publications for qualitative trend synthesis. In this meta-analysis, statistically significant associations revealed that (i) 1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene (p,p'-DDT) and its major metabolite 2,2-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE) were somewhat related to a greater risk of breast cancer. However, this relationship only existed in blood serum but not in adipose tissue. (ii) Breast cancer risk was increased by exposure to chlordane and hexachlorocyclohexane. (iii) Five polychlorinated biphenyls (PCB 99, PCB 105, PCB 118, PCB 138, and PCB 183) can increase the risk of breast cancer. (iv) One phthalate congener (BBP) and one per- and polyfluoroalkyl substance congener (PFDoDA) were negatively associated with breast cancer risk. Unfortunately, heterogeneity was not well explained in our review, and a limited number of available prospective studies investigating the associations between EDC exposure and breast cancer were included in our meta-analysis. To elucidate the overall associations, future large, longitudinal epidemiological investigations are needed.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD 42023420927.

Impact of mixtures of persistent organic pollutants on breast cancer aggressiveness

INTRODUCTION

Breast cancer (BC) is frequent with a poor prognosis in case of metastasis. The role of the environment has been poorly evaluated in its progression. We searched to assess whether a mixture of pollutants could be responsible of BC aggressiveness.

METHODS

Patients undergoing surgery for their BC were prospectively included in the METAPOP cohort. Forty-two POPs were extracted, among them 17 dioxins (PCDD/F), 16 polychlorobiphenyls (PCB), 8 polybromodiphenylethers (PBDE) and 2,2',4,4',5,5'-hexabromobiphenyl (PBB153) were measured in the adipose tissue surrounding the tumor. BC aggressiveness was defined using tumor size and metastasis (distant or lymph nodes). Two complementary models were used to evaluate the impact of the mixture of pollutants: the BKMR (Bayesian Kernel machine regression) and WQS (weighted quantile sum regression) models. The WQS estimates the weight (positive or negative) of a certain chemical based on its quantile and the BKMR model applies a kernel-based approach to estimate posterior inclusion probabilities. The sub-group of patients with a body mass index (BMI) > 22 kg/ m² was also analyzed.

RESULTS

Ninety-one patients were included. Of these, 38 patients presented a metastasis, and the mean tumor size was 25.4 mm. The mean BMI was 24.5 kg/m² (+/- 4.1). No statistical association was found in the general population. However, in patients with a BMI > 22 kg/ m², our mixture was positively associated with tumor size (OR: 9.73 95 %CI: 1.30-18.15) and metastasis (OR = 3.98 95 %CI = 1.09-17.53) using the WQS model. Moreover, using the BKMR model on chemical families, dioxin like chemicals and PCDD were associated with a higher risk of metastasis.

DISCUSSION

These novel findings identified a mixture associated with breast cancer aggressiveness in patients with a BMI > 22 kg/ m².

Work Ability after Breast Cancer: Study of Healthcare Personnel Operating in a Hospital of South Italy

Breast cancer (BrC) treatment can produce disabilities that often impact the quality of daily life and impact the social and working relationships of the patient. This paper looked into the remaining work ability in a group of female healthcare personnel (HCPs) with BrC in Southern Italy. Each HCP was subjected to a medical check, routine blood tests, and a questionnaire on the work ability index (WAI). Of 980 (100%) HCWs undergoing health control, 6% (n = 54) had experienced BRC, and only 66.6% (n = 36) agreed to take part in the study. A total of 28 (78%) were on night shifts. The WAI score was quite low in 5 (13.8%) cases, moderate in 10 (27.7%) cases, good in 14 (38.8%) cases, and excellent in 7 (19.5%) HCWs. Among all health figures, in nurses as well as technical staff, lower WAI scores were observed. HCWs reported various comorbidities, which affected WAI score, such as limited mobility in the upper limbs, arm/shoulder pain, numbness, and lymphoedema. The main complication that negatively affects any work activity is the morbidity in the upper limbs. This seems to affect the ability to perform tasks, and the re-entry to work is highlighted on sick leave days.

Exposure to endocrine disruptors and risk of breast cancer: A systematic review

AIM

The aim of this study was to investigate the association between human exposure to endocrine disruptors (EDs) and the risk of breast cancer.

METHODS

This was a systematic review conducted by searching Cochrane Library, LILACS, Livivo, PubMed, and Science Direct. Observational studies addressing the association between exposure to EDs and breast cancer risk in adults were included. Risk of bias was assessed using the National Toxicology Program's Office of Health Assessment Translation tool.

RESULTS

a total of 37 studies were included. Most studies reported that exposure to organochlorine pesticides, phthalates, heavy metals, and polycyclic aromatic hydrocarbons was associated with increased breast cancer risk.

CONCLUSION

qualitative analysis of observational studies indicates that human exposure to EDs is associated with increased breast cancer risk. Additional studies are needed to determine whether this association is causal.

Long-term atmospheric exposure to PCB153 and breast cancer risk in a case-control study nested in the French E3N cohort from 1990 to 2011

BACKGROUND

Although the genetic and hormonal risk factors of breast cancer are well identified, they cannot fully explain the occurrence of all cases. Epidemiological and experimental studies have suggested that exposure to environmental pollutants, especially those with potential estrogenic properties, as polychlorinated biphenyls (PCBs) may have a role in breast cancer development. Being the most abundantly detected in human tissues and in the environment, congener 153 (PCB153) is widely used in epidemiological studies as indicator for total PCBs exposure.

OBJECTIVES

We aimed to estimate the association between cumulative atmospheric exposure to PCB153 and breast cancer risk.

METHODS

We conducted a case-control study of 5222 cases and 5222 matched controls nested within the French E3N cohort from 1990 to 2011. Annual atmospheric PCB153 concentrations were simulated with the deterministic chemistry-transport model (CHIMERE) and were assigned to women using their geocoded residential history. Their cumulative PCB153 exposure was calculated for each woman from their cohort inclusion to their index date. Breast cancer odds ratios (ORs) associated with cumulative PCB153 exposure and their 95% confidence intervals (95% CIs) were estimated using multivariate conditional logistic regression models.

RESULTS

Overall, our results showed a statistically significant linear increase in breast cancer risk related to cumulative atmospheric exposure to PCB153 as a continuous variable (adjusted OR = 1.19; 95% CI: 1.08-1.31, for an increment of one standard deviation among controls (55 pg/m³)). Among women who became postmenopausal during follow-up, the association remained statistically significant (adjusted OR = 1.23; 95% CI: 1.09-1.39). In analyses by hormone receptors status, the positive association remained significant only for ER-positive breast cancer (adjusted OR = 1.18; 95% CI: 1.05-1.33).

DISCUSSION

This study is the first to have estimated the impact of atmospheric exposure to PCB153 on breast cancer risk. Our results showed a statistically significant increase in breast cancer risk, which may be limited to ER-positive breast cancer. These results warrant confirmation in further independent studies but raise the possibility that exposure to PCB153 increase breast cancer risk.

Exposure to polychlorinated biphenyls and organochlorine pesticides and thyroid cancer in connecticut women

BACKGROUND

Thyroid cancer incidence has increased substantially over the past decades, and environmental risk factors have been suggested to play a role. Polychlorinated biphenyls (PCB) and organochlorine pesticides (OCP) are established thyroid hormone disruptors, but their relationship to thyroid cancer is not known.

METHODS

We investigated the relationship between serum PCB and OCP concentrations and papillary thyroid cancer (PTC) in 250 incident female PTC cases and 250 female controls frequency-matched on age, all residing in Connecticut. Interviews and serum samples were collected from 2010 to 2013. Samples were analyzed for 32 different chemicals using gas chromatography with isotope dilution high resolution mass spectrometry. We calculated odds ratios (OR) and 95% confidence intervals (CI) using single pollutant logistic regression models for concentrations (per interquartile range) of individual PCB/OCP and summed groups of structurally or biologically similar PCB/OCP, adjusted for education, family history of cancer, alcohol consumption, age, and body mass index. Sub-analyses included stratification by tumor size (≤ and >1 cm) and birth before or during peak PCB production (born in 1960 or earlier and born after 1960), as exposures during early life may be important. We also applied three multi-pollutant approaches (standard multi-pollutant regression, hierarchical Bayesian modeling, principal components regression analysis) to investigate associations with co-exposures to multiple PCB/OCPs.

RESULTS

No PCB/OCPs were positively associated with PTC in primary analyses. Statistically significant associations were observed for 9 of the 32 chemicals and 3 summed groups of similar chemicals in the those born during peak production based on single-pollutant models. Multi-pollutant analyses suggested null associations overall.

CONCLUSIONS

Our results using single and multi-pollutant modeling do not generally support an association between PCB or OCP exposure and PTC, but some associations in those born during peak production suggest that additional investigation into early-life exposures and subsequent thyroid cancer risk may be warranted.

Exposure to Endocrine Disrupting Chemicals and Risk of Breast Cancer

Breast cancer (BC) is the second most common cancer and the fifth deadliest in the world. Exposure to endocrine disrupting pollutants has been suggested to contribute to the increase in disease incidence. Indeed, a growing number of researchershave investigated the effects of widely used environmental chemicals with endocrine disrupting properties on BC development in experimental (in vitro and animal models) and epidemiological studies. The complex effects of endocrine disrupting chemicals (EDCs) on hormonal pathways, involving carcinogenic effects and an increase in mammary gland susceptibility to carcinogenesis-together with the specific characteristics of the mammary gland evolving over the course of life and the multifactorial etiology of BC-make the evaluation of these compounds a complex issue. Among the many EDCs suspected of increasing the risk of BC, strong evidence has only been provided for few EDCs including diethylstilbestrol, dichlorodiphenyltrichloroethane, dioxins and bisphenol A. However, given the ubiquitous nature and massive use of EDCs, it is essential to continue to assess their long-term health effects, particularly on carcinogenesis, to eradicate the worst of them and to sensitize the population to minimize their use.

Environmental exposures and breast cancer risk in the context of underlying susceptibility: A systematic review of the epidemiological literature

BACKGROUND

The evidence evaluating environmental chemical exposures (ECE) and breast cancer (BC) risk is heterogeneous which may stem in part as few studies measure ECE during key BC windows of susceptibility (WOS). Another possibility may be that most BC studies are skewed towards individuals at average risk, which may limit the ability to detect signals from ECE.

OBJECTIVES

We reviewed the literature on ECE and BC focusing on three types of studies or subgroup analyses based on higher absolute BC risk: BC family history (Type 1); early onset BC (Type 2); and/or genetic susceptibility (Type 3).

METHODS

We systematically searched the PubMed database to identify epidemiologic studies examining ECE and BC risk published through June 1, 2019.

RESULTS

We identified 100 publications in 56 unique epidemiologic studies. Of these 56 studies, only 2 (3.6%) were enriched with BC family history and only 11% of studies (6/56) were specifically enriched with early onset cases. 80% of the publications from these 8 enriched studies (Type 1: 8/10 publications; Type 2: 8/10 publications) supported a statistically significant association between ECE and BC risk including studies of PAH, indoor cooking, NO₂, DDT; PCBs, PFOSA; metals; personal care products; and occupational exposure to industrial dyes. 74% of Type 3 publications (20/27) supported statistically significant associations for PAHs, traffic-related air pollution, PCBs, phthalates, and PFOSAs in subgroups of women with greater genetic susceptibility due to variants in carcinogen metabolism, DNA repair, oxidative stress, cellular apoptosis and tumor suppressor genes.

DISCUSSION

Studies enriched for women at higher BC risk through family history, younger age of onset and/or genetic susceptibility consistently support an association between an ECE and BC risk. In addition to measuring exposures during WOS, designing studies that are enriched with women at higher absolute risk are necessary to robustly measure the role of ECE on BC risk.

Defining Parallels between the Salivary Glands and Pancreas to Better Understand Pancreatic Carcinogenesis

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor with a dismal prognosis, largely due to its late presentation. Methods for early detection, the development of reliable screening tools, and the identification of sensitive and specific biomarkers have remained essential research priorities to improve early patient management and outcomes. The pancreas and salivary glands share histological and functional similarities, and the salivary glands have demonstrated a role in oral and systemic health. This review focuses on the similarities and differences between the pancreas and salivary glands and how these can inform our understanding of PDAC genesis and early diagnosis. In particular, chemical exposure, which alters salivary gland gene transcription and morphogenesis, may not only directly impact salivary gland regulation but alter pancreatic function via the systemic secretion of growth hormones. Diabetes and obesity are associated with an increased risk of pancreatic cancer, and a link between chemical exposure and the development of diabetes, obesity, and consequently PDAC genesis is proposed. Possible mechanisms include altering salivary or pancreatic morphology and organ function, disrupting endocrine signaling, or altering pro-inflammatory homeostasis. Finally, saliva contains putative specific biomarkers that show promise as non-invasive diagnostic tools for PDAC.