Breast cancer in the Arctic--changes over the past decades

Microbial approaches for remediation of pollutants: Innovations, future outlook, and challenges

Environmental contamination with persistent organic pollutants has emerged as a serious threat of pollution. Bioremediation is a key to eliminate these harmful pollutants from the environment and has gained the interest of researchers during the past few decades. Scientific knowledge upon microbial interactions with individual pollutants over the past decades has helped to abate environmental pollution. Traditional bioremediation approaches have limitations for their applications; hence, it is essential to discover new bioremediation approaches with biotechnological interventions for best results. The developments in various methodologies are expected to increase the efficiency of bioremediation techniques and provide environmentally sound strategies. This paper deals with the profiling of microorganisms present in polluted sites using various techniques such as culture-based approaches and omics-based approaches. Besides this, it also provides up-to-date scientific literature on the microbial electrochemical technologies which are nowadays considered as the best approach for remediation of pollutants. Detailed information about future outlook and challenges to evaluate the effect of various treatment technologies for remediation of pollutants has been discussed.

Exposure to persistent organic pollutants: impact on women's health

This literature review focuses on the causal relationship between persistent organic pollutants (POPs) exposure and women's health disorders, particularly cancer, cardio-metabolic events and reproductive health. Progressive industrialization has resulted in the production of a multitude of chemicals that are released into the environment on a daily basis. Environmental chemicals or pollutants are not only hazardous to our ecosystem but also lead to various health problems that affect the human population worldwide irrespective of gender, race or age. However, most environmental health studies that have been conducted, until recently, were exclusively biased with regard to sex and gender, beginning with exposure studies that were reported mostly in male, occupational workers and animal studies being carried out mostly in male rodent models. Health-related issues pertaining to women of all age groups have not been studied thoroughly and rather disregarded in most aspects of basic health science research and it is therefore pertinent that we address these limitations in environmental health. The review also addresses studies looking at the associations between health outcomes and exposures to POPs, particularly, polychlorinated biphenyls (PCBs), dioxins and pesticides, reported in cohort studies while accounting for gender differences. Considering that current levels of POPs in women can also impact future generations, informative guidelines related to dietary patterns and exposure history are needed for women of reproductive age. Additionally, occupational cohorts of highly exposed women worldwide, such as women working in manufacturing plants and female pesticide applicators are required to gather more information on population susceptibility and disease pathology.

Cancer Incidence and Mortality in Greenland 1983-2014 - Including Comparison With the Other Nordic Countries

BACKGROUND

During the last decades, social and life-style changes in Greenland have led to an increase in the incidence of several non-communicable diseases. Our aim is to present the cancer incidence and mortality in Greenland and compare the results with the other Nordic countries.

METHODS

The data stems from The Danish Cancer Registry and The Danish Register of Causes of Death. Comparable data on cancer incidence and mortality in Denmark, Finland, Iceland, Norway, Sweden, and Greenland are available through collaboration between Nordic Cancer Registries (NORDCAN). We included all individuals residing in Greenland and diagnosed with or died of a cancer from 1983 to 2014.

FINDINGS

The total number of cancer cases in Greenland for the study period was 4716 and there were 3231 cancer deaths. Respiratory and gastrointestinal cancers had the highest incidence as well as mortality in Greenland for the entire time period and for both sexes. Compared to the other Nordic countries, Greenland had significantly higher incidence and mortality rates for several cancers. Cancer of the lip, oral cavity, and pharynx, respiratory cancer, and cancer of unknown sites had the highest incidence rate ratios (2.3-3.9) and mortality rate ratios (2.7-9.9) for both sexes. The time trend from 1983 to 2014 showed a significant increase in cancer incidence in Greenland with nearly the same incidence level as the other Nordic countries. While the cancer mortality decreased in the other Nordic countries during the time period studied, there was no change in the cancer-specific mortality in Greenland.

INTERPRETATIONS

The trends in cancer incidence and mortality in Greenland compared to the other Nordic countries have not been reported earlier. These data underline a need to focus on cancer-specific mortality in Greenland and prevention of high-incidence cancers related to well-established risk factors.

Serum levels of environmental pollutants is a risk factor for breast cancer in Inuit: a case control study

BACKGROUND

Environmental Persistent Organic Pollutants (POPs) can alter the hormone homeostasis by mimicking, interfering or blocking the function of hormones; moreover POPs are hypothesized to modify the risk of breast cancer. The association between POPs and breast cancer has been widely studied but the conclusions are inconsistent. The present study examined the associations between serum levels of POPs and breast cancer with focus on the highly exposed Greenlandic Inuit population.

METHODS

The study design was a case-control study of Inuit women from Greenland. The participants were asked to complete a questionnaire with information on reproductive history and lifestyle and to provide a blood sample. The sampling was carried out in two time periods (2000-2003 and 2011-2014). The serum levels were determined of 14 polychlorinated biphenyls (PCBs), 11 organochlorine pesticides (OCPs), 16 perfluoroalkyl acids (PFAAs), 1 polybrominated biphenyl (PBB), and 9 polybrominated diphenyl ethers (PBDEs). Independent samples t-test was used to compare differences between cases and controls and odds ratios (OR) adjusted for identified confounders were obtained using logistic regression.

RESULTS

The study population included 77 breast cancer cases and 84 controls. The majority of the measured compounds declined significantly from 2000 - 2003 to 2011-2014. However, for the perfluorinated carboxylic acids (PFCAs) an increase was observed. The serum levels were significantly higher in cases compared to controls for the majority of the compounds, and after adjusting for age the difference was maintained for ∑OCP, dichlorodiphenyldichloroethylene (p,p'-DDE), ∑PFAA, ∑perfluorinated sulfonic acids (PFSA), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS). For the lipophilic POPs, high serum levels (middel/highest vs. lowest tertile) of ∑PCB, ∑estrgoenicPCB, PCB99, PCB138, PCB153, PCB170, PCB170, and PCB183 was associated with breast cancer risk; for the amphiphilic PFAAs, high serum levels of ∑PFAA, ∑PFCA, ∑PFSA, perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), PFHxS, and PFOS were associated with breast cancer risk.

CONCLUSION

Significant, positive associations between breast cancer risk and PCBs and PFAAs were observed. The associations indicate that environmental exposure to POPs can be a factor increasing the risk for breast cancer in Inuit women.

Polymorphism in xenobiotic and estrogen metabolizing genes, exposure to perfluorinated compounds and subsequent breast cancer risk: A nested case-control study in the Danish National Birth Cohort

In the present case-cohort study based on prospective data from Danish women, we aimed to estimate the main effect of polymorphisms in genes known to be involved in the steroid hormone metabolic pathway and xenobiotic metabolism on the risk of developing breast cancer. We also studied a possible effect measure modification between genotypes and levels of serum perfluoroalkylated substances (PFASs) on the risk to breast cancer. We have previously reported a weak association between serum PFASs levels and the risk of breast cancer for this study population of Danish pregnant nulliparous women as well as in a smaller case-control study of Greenlandic women. The study population consisted of 178 breast cancer cases and 233 controls (tabnulliparous and frequency matched on age) nested within the Danish National Birth Cohort (DNBC), which was established in 1996-2002. Blood samples were drawn at the time of enrollment (6-14 week of gestation). Serum levels of 10 perfluorocarboxylated acids (PFCAs), 5 perfluorosulfonated acids (PFSAs) and 1 sulfonamide (perflurooctane-sulfonamide, PFOSA) were measured. Genotyping was conducted for CYP1A1 (Ile462Val; rs1048943), CYP1B1 (Leu432Val; rs1056836), COMT (Val158Met; rs4680), CYP17A1 (A1→ A2; rs743572); CYP19A1 (C→T; rs10046) by the TaqMan allelic discrimination method. In overall, no significant associations were found between the investigated polymorphisms and the risk of breast cancer in this study among Danish women. The previously found association between PFOSA and risk of breast cancer did vary between different genotypes, with significantly increased risk confined to homozygous carriers of the following alleles: COMT (Met), CYP17 (A1) and CYP19 (C).

CONCLUSION

Our results indicate that polymorphisms in COMT, CYP17 and CYP19 which are involved in estrogen biosynthesis and metabolism can modulate the potential effects of PFOSA exposure on the development of breast cancer.

Perspective on pre- and post-natal agro-food exposure to persistent organic pollutants and their effects on quality of life

BACKGROUND

Adipose tissue constitutes a continual source of internal exposure to organic pollutants (OPs). When fats mobilize during pregnancy and breastfeeding, OPs could affect foetal and neonatal development, respectively.

SCOPE AND APPROACH

The main aim of this review is to deal with pre- and post-natal external exposure to organic pollutants and their effects on health, proposing prevention measures to reduce their risk. The goal is the development of a biomonitoring framework program to estimate their impact on human health, and prevent exposure by recommending some changes in personal lifestyle habits.

KEY FINDINGS AND CONCLUSIONS

It has been shown that new studies should be developed taking into account their cumulative effect and the factors affecting their body burden. In conclusion, several programs should continuously be developed by different health agencies to have a better understanding of the effect of these substances and to develop a unified public policy.

Obesity, Persistent Organic Pollutants and Related Health Problems

The present review aims to delve into persistent organic pollutants (POPs) , as xenobiotics, in correlation to human health. POPs exhibit a group of common characteristics, including lipophilicity, persistence to decomposition and bioaccumulation in tissues. POPs have been thoroughly studied by former researchers, as they offer a particular interest in the elucidation of metabolic, endocrine and immune perturbation caused by their synergy with intracellular mechanisms. Herein particular focus is attributed to the relationship of POPs with obesity provocation. Obesity nowadays receives epidemic dimensions, as its prevalence elevates in an exponential degree. POPs-induced obesity rotates around interfering in metabolic and endocrinal procedures and interacting with peroxisome-proliferator and retinoic receptors. Moreover, polymorphisms in CYP gene families exert a negative result, as they incapacitate detoxification of POPs. Obesity could be deemed as a multidimensional condition, as various factors interact to lead to an obesogenic result. Therefore, concomitant disorders may occur, from mild to lethal, and get intensified due to POPs exposure. POPs exact function mechanisms remain rather enigmatic, thus further investigation should be prospectively performed, for a more lucid picture of this issue, and, consequently for the establishment of alternative solutions.

Forty years of research concerning children and youth in Greenland: a mapping review

OBJECTIVE

This study undertakes a mapping review of mainly concerning children and youth in Greenland in the period 1976-2016 and reflects on how the research has been conducted and knowledge thereby created about children and youth in Greenland, as well as how the research has been developed over time.

DESIGN

16 online databases; five journals; publication lists originating from seven organisations and ten prominent researchers; and local network and references were used in the search and subsequently screened through the scoping criteria. 342 publications were included, encompassing knowledge based on empirical research on children and youth in Greenland within the broader field of psychology.

RESULTS

The majority of studies, 71%, were conducted through quantitative methods. The qualitative research is represented in 22% of the studies and participatory and action-orientated research is represented in 7% of the studies. The most prominent themes in research concerning children and youth in Greenland were physical problems, which were found in 38% of the studies.

CONCLUSIONS

The result reflects a consistent objectivity and quantitative methodology in health research in Greenland since 1991.The health research thus represents a united research community with a shared methodological research approach, while the local participatory action research projects all appear differentiated. While health research covers a spectrum of psychology related objectives, the methodology traditions reveal a specific kind of knowledge, which has come to determine how the mental health of the Greenlandic children is perceived. We believe that more qualitative and locally grounded approaches need to be organised in order to produce a more nuanced knowledge of the Greenlandic children and youth.

Health effects associated with measured levels of contaminants in the Arctic

The Human Health Assessment Group has over the past decade recommended that effect studies be conducted in the circumpolar area. Such studies examine the association between contaminant exposure in the Arctic populations and health effects. Because foetuses and young children are the most vulnerable, effect studies are often prospective child cohort studies. The emphasis in this article is on a description of the effects associated with contaminant exposure in the Arctic. The main topics addressed are neurobehavioural, immunological, reproductive, cardiovascular, endocrine and carcinogenic effect. For each topic, the association between exposure and effects is described, and some results are reported for similar studies outside the Arctic.

Occupational exposure and risk of breast cancer

Breast cancer is a multifactorial disease and the most commonly diagnosed cancer in women. Traditional risk factors for breast cancer include reproductive status, genetic mutations, family history and lifestyle. However, increasing evidence has identified an association between breast cancer and occupational factors, including environmental stimuli. Epidemiological and experimental studies demonstrated that ionizing and non-ionizing radiation exposure, night-shift work, pesticides, polycyclic aromatic hydrocarbons and metals are defined environmental factors for breast cancer, particularly at young ages. However, the mechanisms by which occupational factors can promote breast cancer initiation and progression remains to be elucidated. Furthermore, the evaluation of occupational factors for breast cancer, particularly in the workplace, also remains to be explained. The present review summarizes the occupational risk factors and the associated mechanisms involved in breast cancer development, in order to highlight new environmental exposures that could be correlated to breast cancer and to provide new insights for breast cancer prevention in the occupational settings. Furthermore, this review suggests that there is a requirement to include, through multidisciplinary approaches, different occupational exposure risks among those associated with breast cancer development. Finally, the design of new epigenetic biomarkers may be useful to identify the workers that are more susceptible to develop breast cancer.

Cancer among circumpolar populations: an emerging public health concern

OBJECTIVES

To determine and compare the incidence of cancer among the 8 Arctic States and their northern regions, with special focus on 3 cross-national indigenous groups--Inuit, Athabaskan Indians and Sami.

METHODS

Data were extracted from national and regional statistical agencies and cancer registries, with direct age-standardization of rates to the world standard population. For comparison, the "world average" rates as reported in the GLOBOCAN database were used.

FINDINGS

Age-standardized incidence rates by cancer sites were computed for the 8 Arctic States and 20 of their northern regions, averaged over the decade 2000-2009. Cancer of the lung and colon/rectum in both sexes are the commonest in most populations. We combined the Inuit from Alaska, Northwest Territories, Nunavut and Greenland into a "Circumpolar Inuit" group and tracked cancer trends over four 5-year periods from 1989 to 2008. There has been marked increase in lung, colorectal and female breast cancers, while cervical cancer has declined. Compared to the GLOBOCAN world average, Inuit are at extreme high risk for lung and colorectal cancer, and also certain rare cancers such as nasopharyngeal cancer. Athabaskans (from Alaska and Northwest Territories) share some similarities with the Inuit but they are at higher risk for prostate and breast cancer relative to the world average. Among the Sami, published data from 3 cohorts in Norway, Sweden and Finland show generally lower risk of cancer than non-Sami.

CONCLUSIONS

Cancer among certain indigenous people in the Arctic is an increasing public health concern, especially lung and colorectal cancer.

EDC-2: The Endocrine Society's Second Scientific Statement on Endocrine-Disrupting Chemicals

The Endocrine Society's first Scientific Statement in 2009 provided a wake-up call to the scientific community about how environmental endocrine-disrupting chemicals (EDCs) affect health and disease. Five years later, a substantially larger body of literature has solidified our understanding of plausible mechanisms underlying EDC actions and how exposures in animals and humans-especially during development-may lay the foundations for disease later in life. At this point in history, we have much stronger knowledge about how EDCs alter gene-environment interactions via physiological, cellular, molecular, and epigenetic changes, thereby producing effects in exposed individuals as well as their descendants. Causal links between exposure and manifestation of disease are substantiated by experimental animal models and are consistent with correlative epidemiological data in humans. There are several caveats because differences in how experimental animal work is conducted can lead to difficulties in drawing broad conclusions, and we must continue to be cautious about inferring causality in humans. In this second Scientific Statement, we reviewed the literature on a subset of topics for which the translational evidence is strongest: 1) obesity and diabetes; 2) female reproduction; 3) male reproduction; 4) hormone-sensitive cancers in females; 5) prostate; 6) thyroid; and 7) neurodevelopment and neuroendocrine systems. Our inclusion criteria for studies were those conducted predominantly in the past 5 years deemed to be of high quality based on appropriate negative and positive control groups or populations, adequate sample size and experimental design, and mammalian animal studies with exposure levels in a range that was relevant to humans. We also focused on studies using the developmental origins of health and disease model. No report was excluded based on a positive or negative effect of the EDC exposure. The bulk of the results across the board strengthen the evidence for endocrine health-related actions of EDCs. Based on this much more complete understanding of the endocrine principles by which EDCs act, including nonmonotonic dose-responses, low-dose effects, and developmental vulnerability, these findings can be much better translated to human health. Armed with this information, researchers, physicians, and other healthcare providers can guide regulators and policymakers as they make responsible decisions.

The organochlorine pesticides residues in the invasive ductal breast cancer patients

Investigation of organochlorine pesticides residues (important environmental contamination causing malignant transformation) in breast cancer patients is valuable to understanding their roles in breast cancer. 75 invasive ductal carcinoma (IDC) patients were enrolled with control of 79 benign breast diseases patients and control of 80 healthy women. Morning fasting blood specimens and adipose tissue specimens beside the primary lesion were detected with gas chromatograph. In blood specimens, both levels of β-HCH and PCTA were higher in IDC than those in both controls (both p<0.05), and increasingly higher among the three IDC degrees. In adipose tissue specimens, all levels of β-HCH, PCTA and pp'-DDE were higher in IDC than those in control (all p<0.05) and increasingly higher among three IDC degrees. The levels of β-HCH, PCTA in both blood specimens and adipose tissue specimens were higher in estrogen receptor (ER) positive IDC than those in ER negative IDC (all p<0.05). The higher level of organochlorine pesticides residues in blood and adipose tissue specimens of IDC infers its association with IDC, but the details remains to reveal, and this study may helpful in this field.

Developmental Exposure to Environmental Toxicants

Children interact with the physical environment differently than adults, and are uniquely susceptible to environmental toxicants. Routes of absorption, distribution, metabolism, and target organ toxicities vary as children grow and develop. This article summarizes the sources of exposure and known adverse effects of toxicants that are ubiquitous in our environment, including tobacco smoke, ethanol, solvents, heavy metals, volatile organic compounds, persistent organic pollutants, and pesticides. Preventive strategies that may be used in counseling children and their families are highlighted.

Chemical compounds from anthropogenic environment and immune evasion mechanisms: potential interactions

An increasing number of studies suggest an important role of host immunity as a barrier to tumor formation and progression. Complex mechanisms and multiple pathways are involved in evading innate and adaptive immune responses, with a broad spectrum of chemicals displaying the potential to adversely influence immunosurveillance. The evaluation of the cumulative effects of low-dose exposures from the occupational and natural environment, especially if multiple chemicals target the same gene(s) or pathway(s), is a challenge. We reviewed common environmental chemicals and discussed their potential effects on immunosurveillance. Our overarching objective was to review related signaling pathways influencing immune surveillance such as the pathways involving PI3K/Akt, chemokines, TGF-β, FAK, IGF-1, HIF-1α, IL-6, IL-1α, CTLA-4 and PD-1/PDL-1 could individually or collectively impact immunosurveillance. A number of chemicals that are common in the anthropogenic environment such as fungicides (maneb, fluoxastrobin and pyroclostrobin), herbicides (atrazine), insecticides (pyridaben and azamethiphos), the components of personal care products (triclosan and bisphenol A) and diethylhexylphthalate with pathways critical to tumor immunosurveillance. At this time, these chemicals are not recognized as human carcinogens; however, it is known that they these chemicalscan simultaneously persist in the environment and appear to have some potential interfere with the host immune response, therefore potentially contributing to promotion interacting with of immune evasion mechanisms, and promoting subsequent tumor growth and progression.

Environmental Polychlorinated Biphenyl Exposure and Breast Cancer Risk: A Meta-Analysis of Observational Studies

BACKGROUND

Association between polychlorinated biphenyl (PCB) exposure and breast cancer risk has been widely studied, but the results remain controversial. We performed a meta-analysis to evaluate the evidences from observational studies on PCB exposure and breast cancer risk.

METHODS

Relevant studies with data on internal PCB dose were identified from PubMed, EMBASE, CBM and CNKI databases through November 2014. Multivariable-adjusted odds ratio (OR) with 95% confidence intervals (CIs) were applied to assess the association between PCB exposure and breast cancer risk. Heterogeneity test, sensitivity analysis, subgroup analysis and publication bias test were also performed. To further explore the association between specific groups of PCB congeners and breast cancer, we examined the PCB congeners classified, according to their structural, biological and pharmacokinetics properties, as group I (potentially estrogenic), group II (potentially anti-estrogenic and immunotoxic, dioxin-like), and group III (phenobarbital, CYP1A and CYP2B inducers, biologically persistent).

RESULTS

Of 660 studies screened, 25 studies which met criteria were selected, involving a total of 12866 participants (6088 cases and 6778 controls) from eight countries. The results showed that the risk of breast cancer was associated with group II (OR = 1.23, 95% CI: 1.08-1.40) and group III (OR = 1.25, 95% CI: 1.09-1.43) PCBs, but not with group I (OR = 1.10, 95%CI: 0.97-1.24) PCBs or total PCB exposure (OR = 1.09, 95%CI: 0.97-1.22).

CONCLUSIONS

Our meta-analysis based on the selected studies found group II and group III PCB exposure might contribute to the risk of breast cancer. More studies in developing countries with higher PCB levels are needed, as well as studies to explore the relationships between mixtures of organochlorine compounds and breast cancer risk.

Breast cancer risk after exposure to perfluorinated compounds in Danish women: a case-control study nested in the Danish National Birth Cohort

OBJECTIVE

Animal studies have indicated that perfluoroalkylated substances (PFAS) increase mammary fibroadenomas. A recent case-control study in Greenlandic Inuit women showed an association between the PFAS serum levels and breast cancer (BC) risk. The present study evaluates the association between serum levels of PFAS in pregnant Danish women and the risk of premenopausal BC during a follow-up period of 10-15 years using prospectively collected exposure data during the pregnancy.

METHODS

Questionnaire and blood samples were taken during 1996-2002 and at the end of follow-up, all 250 BC cases and 233 frequency-matched controls were chosen for further analyses. Serum levels of ten perfluorocarboxylated acids, five perfluorosulfonated acids, and one sulfonamide (perflurooctane-sulfonamide, PFOSA) were determined by liquid chromatography-tandem mass spectrometry with electrospray ionization in negative mode. Computer-assisted telephone interviews taken during pregnancy provided data on potential confounders.

RESULTS

Weak positive and negative insignificant associations were found between BC risk and levels of perfluorooctane sulfonamide (PFOSA) and perfluorohexanesulfonate (PFHxS), respectively. Grouped into quintile, the BC cases had a significant positive association with PFOSA at the highest quintiles and a negatively association for PFHxS. Sensitivity analyses excluding uncertain cases caused stronger data for PFOSA and weaker for PFHxS. No further significant associations were observed.

CONCLUSIONS

This study does not provide convincing evidence for a causal link between PFAS exposures and premenopausal BC risks 10-15 years later.

Biomonitoring and hormone-disrupting effect biomarkers of persistent organic pollutants in vitro and ex vivo

Persistent organic pollutants (POPs) include lipophilic legacy POPs and the amphiphilic perfluorinated alkyl acids (PFAAs). They have long half-lives and bioaccumulate in the environment, animals and human beings. POPs possess toxic, carcinogenic and endocrine-disrupting potentials. Endocrine-disrupting chemicals (EDCs) are compounds that either mimic or block endogenous hormones and thus disrupt the normal hormone homeostasis. Biomonitoring assesses the internal doses of a person to provide information about chemical exposures. Effect biomarkers assess chemicals potential to affect cellular functions in vivo/ex vivo. Human beings are exposed to complex mixtures of chemicals, having individually very different biological potentials and effects. Therefore, the assessment of the combined, integrated biological effect of the actual chemical mixture in human blood is important. In vitro and ex vivo cell systems have been introduced for the assessment of the integrated level of xenobiotic cellular effects in human beings. Ex vivo studies have shown geographical differences in bioaccumulated POP serum levels, being reflected by the combined biomarker effects of the complex mixture extracted from human serum. Xenohormone receptor transactivities can be used as an ex vivo integrated biomarker of POP exposure and effects. Epidemiological and in vitro/ex vivo studies have supported the potential impact of the combined effect of serum POPs on the activity of hormone and/or dioxin receptors as a risk factor for human health. With focus on hormone disruption, this MiniReview will give an update on recent POP-related endocrine-disrupting effects in vitro/ex vivo/in vivo and some related genetic data.

Polymorphisms in phase I and phase II genes and breast cancer risk and relations to persistent organic pollutant exposure: a case-control study in Inuit women

BACKGROUND

We have previously reported that chemicals belonging to the persistent organic pollutants (POPs) such as perfluorinated compounds (PFAS) and polychlorinated biphenyls (PCBs) are risk factors in Breast Cancer (BC) development in Greenlandic Inuit women. The present case-control study aimed to investigate the main effect of polymorphisms in genes involved in xenobiotic metabolism and estrogen biosynthesis, CYP1A1, CYP1B1, COMT and CYP17, CYP19 and the BRCA1 founder mutation in relation to BC risk and to explore possible interactions between the gene polymorphisms and serum POP levels on BC risk in Greenlandic Inuit women.

METHODS

The study population consisted of 31 BC cases and 115 matched controls, with information on serum levels of POPs. Genotyping was conducted for CYP1A1 (Ile462Val; rs1048943), CYP1B1 (Leu432Val; rs1056836), COMT (Val158Met; rs4680), CYP17A1 (A1> A2; rs743572); CYP19A1 (C> T; rs10046) and CYP19A1 ((TTTA)n repeats) polymorphisms and BRCA1 founder mutation using TaqMan allelic discrimination method and polymerase chain reaction based restriction fragment length polymorphism. The χ2 -test was used to compare categorical variables between cases and controls and the odds ratios were estimated by unconditional logistic regression models.

RESULTS

We found an independent association of CYP1A1 (Val) and CYP17 (A1) with BC risk.Furthermore, an increased BC risk was observed for women with high serum levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) and carriers of at least: one CYP1A1 variant Val allele; one variant COMT Met allele; or the common CYP17 A1 allele. No combined effects were seen between PFAS exposure and CYP1B1 and CYP19 polymorphisms. The risk of BC was not found significantly associated with exposure to PCBs and OCPs, regardless of genotype for all investigated SNPs. The frequency of the Greenlandic founder mutation in BRCA1 was as expected higher in cases than in controls.

CONCLUSIONS

The BRCA1 founder mutation and polymorphisms in CYP1A1 (Val) and CYP17 (A1) can increase the BC risk among Inuit women and the risk increases with higher serum levels of PFOS and PFOA. Serum PFAS levels were a consistent risk factor of BC, but inter-individual polymorphic differences might cause variations in sensitivity to the PFAS/POP exposure.

Health of Indigenous Circumpolar Populations

Indigenous circumpolar populations have experienced profound transitions in lifeways over the past half-century as a result of economic development. Although there have been positive aspects of this social transformation, most circumpolar groups today have a triple burden of disease, with a modestly elevated infectious disease level, an elevated and increasing burden of chronic conditions such as obesity and cardiovascular disease, and high rates of mental health–related challenges. The health of contemporary circumpolar populations is not easily characterized because of dramatic regional differences that stem from socioeconomic disparities among nonindigenous groups, individual population histories, lifestyle factors, environmental pollution, and underlying biological variation. Overall health and well-being range from excellent among the Sami of Sweden and Norway to extremely poor among marginalized native populations in northern Russia. Circumpolar groups today are not only threatened by continued regional economic development and pollution, but also uniquely vulnerable to global climate change.

New insight into Ki67 expression at the invasive front in breast cancer

Purpose

To investigate the distribution of Ki67+ cells in breast cancer in relation to clinical-pathological parameters and prognosis.

Materials and Methods

Ki67 expression status was detected in 1,086 breast cancer specimens using immunohistochemistry staining and examining the relationship between the Ki67+ cells' location. Subsequently, clinical-pathological parameters and prognosis were determined.

Results

In total, Ki67 protein expression was found in 781 (71.92%) of the 1,086 breast cancer specimens. Among the 781 Ki67+ cases, 461 were defined as diffuse type and 320 were defined as borderline type. After universal correlation analysis, significant differences were observed in age, histological grade, metastatic nodes, postoperative distant metastasis, and molecular subtype between Ki67+ and Ki67− cases (P = 0.01, 0.001, 0.001, 0.001, and 0.001, respectively). After subgroup analysis, the borderline cases were found to be characterized by a high distant metastasis rate compared to the diffuse cases as well as the Ki67− cases (P = 0.001). No differences were observed between diffuse type or Ki67− cases (P = 0.105). Multivariate analysis showed that age, tumor size, histological grade, lymph node metastasis, molecular subtype, and the Ki67 distribution pattern were observed to be related to postoperative distant metastasis (all P<0.05). Furthermore, borderline type was shown to attain a significantly more distant bone and liver metastasis and worse disease-specific survival than the other types (P = 0.001). In the Cox regression test, the Ki67 distribution pattern was detected as an independent prognostic factor (P = 0.001).

Conclusion

The distribution pattern of Ki67 may be a new independent prognostic factor for breast cancer.

Breast cancer in the Arctic--changes over the past decades

The purpose of this study is to review the current literatures on breast cancer (BC) in the Arctic, especially the trends in incidence during the last decades and the possible explanations. The design of this study is a literature review. The scientific literature concerning BC were reviewed, especially focusing on the Arctic and the special conditions that exist in this region. Breast cancer incidence is increasing all over the world, including in the Arctic. The enormous transition in health conditions and lifestyle in the Arctic might be contributing to the known risk factors. In Greenland, the age at menarche has diminished by 3 years during the course of 100 years, and the number of children per women as well as the duration of breastfeeding is decreasing. Obesity and intake of saturated fat is increasing and the intake of traditional food rich in unsaturated fat and vitamin D decreasing. Smoking and alcohol consumption in the Arctic has been relatively high but is now decreasing. More focus on genetic susceptibility in relation to BC has identified the specific BRCA1 founder mutation in the Greenlandic population, which might appear to be an important risk factor. However, the known established risk factors alone cannot account for the increasing trend observed. Studies suggest that environmental contaminants such as persistent organic pollutants (POPs) including perfluorinated compounds increase the risk of BC possibly in conjunction with certain genetic polymorphisms involved in carcinogen activation. The lipophilic POPs such as polychlorinated biphenyls and organochlorine pesticides are found at very high levels in the Arctic population. Several factors can explain the increasing incidence of BC in the Arctic. The transition in lifestyle and health conditions unfortunately increases the known risk factors of BC. Moreover, the population of the Arctic might show up to be especially vulnerable because of the contemporary high burden of POPs and genetic susceptibility.