Serum polychlorinated biphenyl (PCB) levels and risk of testicular germ cell tumors: A population-based case-control study in Connecticut and Massachusetts

Level of polychlorinated biphenyls in tumor and blood serum of breast cancer patients and control subjects from Punjab, Pakistan

The current study examined the level of Polychlorinated biphenyls (PCBs) in tumor and blood serum of female breast cancer patients and control individuals recruited from Punjab, Pakistan. Breast tumor and blood serum from 40 patients and only blood serum from ten control subjects were obtained and concentration of 32 PCB congeners was analyzed through Gas chromatography coupled with Mass spectrophotometry. Sociodemographic variables of the patients along with essential clinical and haematological parameters were taken as covariates. Tumor reflects the highest median (min-max) concentration (ng g-1 lw) of ƩPCBs at 115.94 (0.05-17.75) followed by 16.53 (0.09-2.94) and 5.24 (0.01-0.59) in blood serum of cancer patients and control group respectively. Median concentrations (ng g-1 lw) of non-dioxine like ƩPCBs were considerably higher at 83.04, 32.89 and 4.27 compared to 13.03 and 3.50 and 0.97 for dioxin like ƩPCBs in tumor, serum of breast cancer patients and control subjects respectively. PCB-87 was most dominant congeners in tumor followed by PCB-170 and -82 whereas PCB-28 and -52 reflected greatest contribution in serum of breast cancer patients. Blood haemoglobin, potassium and chloride ions showed significant positive whereas body mass index reflect inverse relationship when regressed with ƩPCBs in tumor. This pioneer study depicts elevated concentrations of PCBs in patients compared to control, reflecting potential positive association of PCBs with breast cancer which need further confirmation. We concluded that chronic exposure to PCBs might be associated with an increasing number of breast cancer incidences in developing countries like Pakistan, which should be further elucidated through detail in vitro and in vivo studies.

Endocrine-disrupting chemicals (EDCs) and cancer: new perspectives on an old relationship

PURPOSE

Environmental endocrine-disrupting chemicals (EDCs) are a mixture of chemical compounds capable to interfere with endocrine axis at different levels and to which population is daily exposed. This paper aims to review the relationship between EDCs and breast, prostate, testicle, ovary, and thyroid cancer, discussing carcinogenic activity of known EDCs, while evaluating the impact on public health.

METHODS

A literature review regarding EDCs and cancer was carried out with particular interest on meta-analysis and human studies.

RESULTS

The definition of EDCs has been changed through years, and currently there are no common criteria to test new chemicals to clarify their possible carcinogenic activity. Moreover, it is difficult to assess the full impact of human exposure to EDCs because adverse effects develop latently and manifest at different ages, even if preclinical and clinical evidence suggest that developing fetus and neonates are most vulnerable to endocrine disruption.

CONCLUSION

EDCs represent a major environmental and health issue that has a role in cancer development. There are currently some EDCs that can be considered as carcinogenic, like dioxin and cadmium for breast and thyroid cancer; arsenic, asbestos, and dioxin for prostate cancer; and organochlorines/organohalogens for testicular cancer. New evidence supports the role of other EDCs as possible carcinogenic and pregnant women should avoid risk area and exposure. The relationship between EDCs and cancer supports the need for effective prevention policies increasing public awareness.

Environmental disruptors and testicular cancer

PURPOSE

Testicular cancer (TC) is the most common malignancy among young adult males. The etiology is multifactorial, and both environmental and genetic factors play an essential role in the origin and development of this tumor. In particular, exposure to environmental endocrine disruptors (EEDs), resulting from industrialization and urbanization, seems crucial both in pre-and postnatal life. However, the lack of long-term studies on a wide caseload and the difficulty in evaluating their toxic effects in vivo make it challenging to establish a causal link. This review aims to discuss the main human epidemiological studies currently available in the literature to define a possible association between these chemicals and TC.

METHODS

A comprehensive Medline/PubMed and Embase search was performed, selecting all relevant, peer-reviewed papers in English published from 2002 to January 2022. Other relevant papers were selected from the reference lists.

RESULTS

To date, literature evidence is limited due to the scarcity and heterogeneity of human studies and shows controversial data, highlighting the complexity of the topic. However, most human epidemiological studies seem to point toward a correlation between EEDs exposure and TC.

CONCLUSION

Although the molecular mechanisms are not yet fully understood, the role of EEDs in TC onset is plausible, but several factors, such as the individual genetic background, the exposure time, and the complex mechanism of action of these chemicals, do not allow defining the causal link with certainty and make further studies necessary to investigate this complex topic.

A Review of Polychlorinated Biphenyls (PCBs) Pollution in the Air: Where and How Much Are We Exposed to?

Polychlorinated biphenyls (PCBs) were widely used in industrial and commercial applications, until they were banned in the late 1970s as a result of their significant environmental pollution. PCBs in the environment gained scientific interest because of their persistence and the potential threats they pose to humans. Traditionally, human exposure to PCBs was linked to dietary ingestion. Inhalational exposure to these contaminants is often overlooked. This review discusses the occurrence and distribution of PCBs in environmental matrices and their associated health impacts. Severe PCB contamination levels have been reported in e-waste recycling areas. The occurrence of high PCB levels, notably in urban and industrial areas, might result from extensive PCB use and intensive human activity. Furthermore, PCB contamination in the indoor environment is ten-fold higher than outdoors, which may present expose risk for humans through the inhalation of contaminated air or through the ingestion of dust. In such settings, the inhalation route may contribute significantly to PCB exposure. The data on human health effects due to PCB inhalation are scarce. More epidemiological studies should be performed to investigate the inhalation dose and response mechanism and to evaluate the health risks. Further studies should also evaluate the health impact of prolonged low-concentration PCB exposure.

Cancer Risk following Residential Exposure to Airborne Polychlorinated Biphenyls: A Danish Register-Based Cohort Study

BACKGROUND

Polychlorinated biphenyls (PCBs) are biopersistent chemicals classified as human carcinogens. This classification is primarily based on evidence on higher-chlorinated PCBs found in food. The carcinogenic potential of airborne lower-chlorinated PCBs remains largely unexplored.

OBJECTIVES

We aimed to investigate cancer risk following residential exposure to airborne PCBs.

METHODS

Cancer risk was examined in the Health Effects of PCBs in Indoor Air (HESPAIR) cohort of 38,613 residents of two partly PCB-contaminated residential areas in Greater Copenhagen, identified by nationwide registries. PCB exposure was based on relocation dates and indoor air PCB measurements in subsets of apartments. Cancer diagnoses were extracted from the Danish Cancer Registry for the follow-up period of 1970-2018. We estimated adjusted hazard ratios with time-varying cumulative exposure and a 10-y lag using Cox regression.

RESULTS

Overall risk of cancer was not associated with PCByear, [hazard ratio (HR) for high-exposed vs. low-exposed =0.98; 95% confidence interval (CI): 0.88, 1.09], but residents exposed to ≥3,000 ng/m3 PCB×year had higher risk of liver cancer (HR =2.81; 95% CI: 1.28, 6.15) and meningiomas (HR =3.49; 95% CI: 1.84, 6.64), with indications of exposure-response relationships. Results were suggestive of a higher risk of pancreatic cancer (HR =1.59; 95% CI: 0.95, 2.64) at the highest aggregated PCB level. For testis cancer, a higher risk was observed among residents exposed to 300-949 ng/m3 PCB×year relative to residents exposed to <300 ng/m3 PCB×year (HR =2.97; 95% CI: 1.41, 6.28), but the risk was not higher for residents exposed to ≥950 ng/m3 PCB×year. Apart from this, the risk of specific cancers was similar across exposure groups.

DISCUSSION

In this, to our knowledge, first population-based cohort study of residential exposure to airborne PCBs, we found no association between exposure to PCBs in indoor air in private homes and the risk for most of the specific cancers. Higher risk of liver cancer and meningiomas were observed. https://doi.org/10.1289/EHP10605.

Endocrine Disrupting Chemicals and Risk of Testicular Cancer: A Systematic Review and Meta-analysis

The incidence of many hormone-dependent diseases, including testicular cancer, has sharply increased in all high-income countries during the 20th century. This is not fully explained by established risk factors. Concurrent, increasing exposure to antiandrogenic environmental endocrine disrupting chemicals (EDCs) in fetal life may partially explain this trend. This systematic review assessed available evidence regarding the association between environmental EDC exposure and risk of testicular cancer (seminomas and nonseminomas). Following PRISMA guidelines, a search of English peer-reviewed literature published prior to December 14, 2020 in the databases PubMed and Embase® was performed. Among the 279 identified records, 19 were eligible for quality assessment and 10 for further meta-analysis. The completeness of reporting was high across papers, but over 50% were considered subject to potential risk of bias. Mean age at diagnosis was 31.9 years. None considered effects of EDC multipollutant mixtures. The meta-analyses showed that maternal exposure to combined EDCs was associated with a higher risk of testicular cancer in male offspring [summary risk ratios: 2.16, (95% CI:1.78-2.62), 1.93 (95% CI:1.49-2.48), and 2.78 (95% CI:2.27-3.41) for all, seminoma, and nonseminoma, respectively]. Similarly, high maternal exposures to grouped organochlorines and organohalogens were associated with higher risk of seminoma and nonseminoma in the offspring. Summary estimates related to postnatal adult male EDC exposures were inconsistent. Maternal, but not postnatal adult male, EDC exposures were consistently associated with a higher risk of testicular cancer, particularly risk of nonseminomas. However, the quality of studies was mixed, and considering the fields complexity, more prospective studies of prenatal EDC multipollutant mixture exposures and testicular cancer are needed.

Dataset of testicular germ cell tumors (TGCT) risk associated with serum polychlorinated biphenyl (PCB) by age at diagnosis and histologic types

In a population-based case control study of testicular germ cell tumors (TGCT), we reported a strong positive association between serum levels of Wolff's Group 1 (potentially estrogenic) polychlorinated biphenyl (PCBs) and risk of TGCT, and the observed associations were similar for both seminoma and non-seminoma. While the observed specific associations between TGCT and Wolff's Group 1 PCBs cannot be easily explained by bias or confounding, a question can still be asked, that is, could the relationship between PCBs and TGCT differ by age at diagnosis? PCBs tend to bioaccumulate, with more heavily chlorinated PCB congeners tending to have longer half-lives. Half-lives of PCB congeners were reported ranging from 4.6 years for PCB-28 to 41.0 years for PCB-156. The half-life for the heavy PCB congeners (17.8 years) was found to be approximately twice that for the light PCBs (9.6 years) in early studies. Therefore, the same PCB concentration measured in a 20-year-old vs. a 55-year-old is unlikely to represent the same lifetime PCB exposure or type of PCB exposure. In this analysis, we stratified the data by median age of diagnosis of TGCT and further stratified by histologic type of TGCT (seminoma vs non-seminoma) to explore if the risk of TGCT associated with PCB exposures differs by age.