Archive for category ‘cancer‘

60 Scientists and NGOs Sound Joint Warning on Plastics Chemical

Scientists and NGOs concerned about the health impacts of bisphenol A

PRESS RELEASE, 23rd JUNE 2010

An unprecedented 60 scientists and international environment, health and women’s organisations from around the globe have jointly written to the European Food Safety Authority (EFSA) stating that

“action is necessary to reduce the levels of Bisphenol-A (BPA) exposure, particularly in groups at highest risk, namely young infants and pregnant mothers.”

[Quotes from some of the participating scientists and NGOs can be found towards the end of this release.]

In total, 41 NGOs and 19 scientists from 15 countries from across the globe (including 9 from the UK) have signed the letter. The letter comes on the eve of a new scientific opinion to be released by the EFSA on the safety of Bisphenol A in food contact materials expected in early July 2010. EFSA was requested by the European Commission to assess the latest science on Bisphenol A, and if necessary, to update the existing Tolerable Daily Intake (TDI) (a specific amount in food or drinking water that can be ingested (orally) over a lifetime without an appreciable health risk).

Bisphenol A is a mass produced chemical used in the manufacture of polycarbonate plastics that are clear and nearly shatter-proof. It can be found in plastics used for food and beverages, such as baby bottles, sports water bottles, as an epoxy resin in canned food and drinks, plastic food storage containers, tableware and in other products, including dental sealants, and has been found to leach into food and drink.

There have been long standing concerns about the health impacts of bisphenol A, due to scientific studies that have shown it has hormone disrupting effects at extremely low levels of exposure. Human bio-monitoring studies have shown that the vast majority of people in developed countries are exposed to Bisphenol-A.

EFSA’s previous opinions in 2007 and 2008 predominantly relied upon a handful of industry backed scientific papers that have expressed no concerns about our levels of BPA exposure. The letter from scientists and NGOs highlights scientific criticism in academic journals regarding these papers as compared to the “several hundred peer reviewed scientific papers have been published that have highlighted potential adverse health effects associated with BPA exposures”

The letter also draws attention to some of the new studies which have raised risks of exposure relating to a potential increased likelihood of developing ‘diabetes’, ‘developmental programming’ and ‘breast cancer’. Bisphenol A exposure at environmentally relevant levels commonly found in the environment in developed countries has also been repeatedly linked by independent university – based scientists to a number of other serious chronic health conditions.

Despite EFSA’s pivotal position in setting chemical food safety levels across the EU, Sweden and Germany have become the third and fourth most recent EU member states, alongside France and Denmark, to take action ahead of the EFSA review.

Andreas Carlgren, Sweden’s Environment Minister stated, on 11th May 2010, that

“If the EU will not quickly forbid the hormone disrupting substance bisphenol in baby-bottles Sweden will precede with a national prohibition.”

The President of the German Federal Environment Agency on the 9th June also broke from EFSA policy by issuing new guidance calling on

“manufacturers, importers and users of bisphenol A to use alternative substances that pose less risk to human health and the environment in all areas of use that significantly contribute to exposure”.

Regulators in Canada and the USA have already taken action to limit BPA exposure, for example in its use in baby bottles. As yet there has been no similar action at the European Union level.

A number of EU member states continue to back a common approach across the EU on bisphenol A. Tim Smith, the head of the UK Food Standards Agency, declared in an internal FSA report on the 12th May, 2010 that he ‘considers it important to have an agreed position across the EU’ and that the FSA will only ‘revise our position in line with it the EFSA Review if it is considered necessary’, despite the action that is being taken elsewhere across the EU.

The EFSA have already delayed publication of its review, as explained on its website:

To give the European Commission an up-to-date overview of the safety of BPA, EFSA will now deliver a scientific opinion in early July rather than end of May. This is due to the need for the Panel to consider hundreds of studies in its review and analysis of the most recent scientific literature.

The letter from scientists and organisations opens by ‘welcoming this announcement’ issued at the 11th hour that EFSA has finally agreed to examine hundreds of non-industry backed scientific papers.

The letter was drafted by Breast Cancer UK and Prof. Fredrick vom Saal, Curators Professor of Biological Sciences, University of Missouri-Columbia who has been awarded by his peers for his work on Bisphenol-A and is a recognised leader in this field. The effort was also coordinated by the Brussels based Health and Environment Alliance (HEAL).

Prof. vom Saal stated in response to the publication of the letter that:

“At the heart of the debate over BPA lies an outdated set of guidelines used by regulatory agencies that are based on approaches to evaluating the safety of chemicals established over 50 years ago. Thus, 21st century research approaches have provided overwhelming scientific evidence of harm in hundreds of published reports, but these findings are being rejected for consideration because they do not conform to the outdated testing guidelines.

“This has left regulatory agencies to rely entirely on industry-funded research that used ‘approved’ testing methods that are crude and insensitive, and it is not surprising that 100% of these industry-funded studies conclude that BPA causes no harm.

“The only rational path for European regulators is to take decisive action to reduce human exposure to BPA. The overwhelming nature of the total scientific evidence mandates this as a priority.”

Clare Dimmer, Chair of Trustees Breast Cancer UK and former breast cancer patient stated:

“Breast cancer is the most common cancer across Europe and has been increasing rapidly regardless of the costly and expensive efforts made by Governments to improve screening, treatment, and increase research. It must now be time that regulators act on the science and begin to take a precautionary approach to hazardous chemicals like bisphenol-A found in our everyday products.”

Lisette van Vliet, Ph.D. the Toxics Policy Advisor at HEAL said:

“It is high time that EFSA caught up to the overwhelming science showing genuine reasons for concern about our daily exposure to BPA.”

Participating scientists and organisations were given the opportunity to provide a quote for this press release; those that responded have been included below. This does not preclude participating organisations providing their own releases, supporting statements and additional comments.

Prof. Andrew Watterson, Occupational and Environmental Health Research Group, University of Stirling, said:

“It’s worrying, considering the weight of the scientific evidence, that strong action to reduce human exposure is yet to be taken. Hundreds of academic studies have explicitly raised the risks of developmental harm to foetuses and young children from exposure to BPA and this should dictate a strong precautionary policy response from European regulators. If this is not forthcoming, the UK Government must intervene as other European countries are already doing so.”

Daniela Hoffmann, Chemicals Expert, GLOBAL 2000/Friends of the Earth Austria:

“EFSA has to finally acknowledge the overwhelming scientific evidence concerning the risk BPA poses to human health.”

Sarah Häuser, Chemicals Expert BUND / Friends of the Earth Germany:

“The existing Tolerable Daily Intake for BPA does not protect human health. In animal experiments and biomonitoring studies, BPA doses much smaller than those estimated as being safe by EFSA were linked to chronic conditions health damages like diabetes and cardiovascular diseases. It’s time to take action now.”

For further information please contact:

Hratche Koundarjian, Campaign Manager, Breast Cancer UK, Charity No: 1088047, T: 07905 911 039, E: hratche@breastcanceruk.org.uk, W: www.breastcanceruk.org.uk / www.nomorebpa.org.uk

Letter and Signatories:

Prof. Klaus-Dieter Jany, Chair of the CEF Panel

European Food Safety Authority

Largo N. Palli 5/A, 43121 Parma, Italy

23rd June 2010

Dear Prof. Jany,

We are writing to welcome the announcement on the European Food Safety Authority (EFSA) website that the CEF panel will be considering ‘hundreds of studies in its review and analysis of the most recent scientific literature’ in its review of the TDI of bisphenol-A in food contact products.

Over the last decade and a half, a substantive body amounting to several hundred peer reviewed scientific papers, have been published that have highlighted potential adverse health effects associated with BPA exposures, at internal doses relevant to levels of biologically active BPA found in humans.

As a March 2010 Review (Vandenberg et al) of 80 bio-monitoring studies of BPA in Environmental Health Perspectives makes clear;

‘The two toxicokinetic studies performed to date, which suggest that human exposure is negligible, have significant flaws and are therefore not reliable for risk assessment purposes.’

However, in its prior risk assessments of BPA, EFSA only relied on a small number of studies rather than the much larger number that the United States Food and Drug Administration recently recognised as valid and of high utility in its risk assessment of BPA, and which led the FDA to express concern about the health hazards posed by BPA.

Only a tiny minority of studies have articulated that BPA exposure is completely safe, and many of these research papers have been criticised in academic commentaries and responses as having serious flaws, but it is these few flawed studies that EFSA previously relied on to declare BPA safe.

For example, a letter co-authored by 24 scientists published in the February 2010 edition of Toxicological Sciences states;

‘Publishing studies that conclude no harm in response to low doses of endocrine disrupting chemicals, when the studies did not include a positive control (Tyl et al., 2002), included inappropriate doses of positive controls (Ryan et al., 2009; Tyl et al., 2008), or included positive controls that showed no effect (Cagen et al., 1999), is inappropriate in peer-reviewed journals (Myers et al., 2009a,b; vom Saal and Welshons, 2006). Such studies violate basic principles of study design.’

Many scientific studies are now calling into question the safety of BPA. For example, a recent study has highlighted that BPA may contribute to metabolic disorders relevant to glucose homeostasis, and suggests that BPA may be a risk factor for diabetes (Alonso-Magdalena et al., 2010). Moreover, experiments at Yale university report that BPA may induce altered developmental programming (Bromer et al.,2010), and Doherty et al (2010) of Yale university have published a study which raises the concern about epigenetic effects of BPA on the regulation of the mammary gland, with potential implications for breast cancer risk. Endometriosis is also a concern as work by Signorile et al (2010) highlights that pre-natal exposure of mice to bisphenol-A causes an endometriosis-like response in female offspring.

It is therefore our opinion that any objective and comprehensive review of the scientific literature will lead to the conclusion that action is necessary to reduce the levels of BPA exposure, particularly in groups at highest risk, namely young infants and pregnant mothers.

There are an increasing number of countries that are either already committed to this course of action, or have signalled that they will soon be undertaking similar measures.

We share the concerns of these Governments and regulators and believe that reducing BPA exposure to these groups is both scientifically sound and in the best interest of public health.

As such, we call on you as the Chair of the CEF panel and the CEF Committee Members in their ongoing review to include all relevant studies, including bio-monitoring studies, and based on that evidence we conclude that there is a strong scientific mandate for action.

Yours sincerely,

  1. Benson Akingbemi, Associate Professor, Department of Anatomy, Physiology and Pharmacology, Auburn University, Auburn, USA.
  2. Prof. Dr. Ibrahim Chahoud, Institute of Clinical Pharmacology and Toxicology, Dept. of Toxicology, Charité – Universitätsmedizin Berlin
  3. André Cicolella, Dipl Eng chemist-toxicologist.
  4. Prof. Patricia Hunt, Meyer Distinguished Professor, School of Molecular Biosciences, Washington State University
  5. Prof. Maricel V. Maffini. Ph.D. Research Assistant Professor. Department of Anatomy and Cellular Biology, Tufts University School of Medicine
  6. Jane Muncke, Ph.D, Environmental Toxicologist, Emhart Glass SA, Switzerland.
  7. John Peterson Myers, Ph.D., Chief Scientist, Environmental Health Sciences, Charlottesville VA.
  8. Angel Nadal, PhD, Professor of Physiology, Instituto de Bioingeniería and CIBERDEM, Universidad Miguel Hernández de Elche, Spain.
  9. Dr John Newby, Medical Information Scientist for the Cancer Prevention Society and Former Member of the Developmental Toxico-Pathology Research Group, Department of Human Anatomy & Cell Biology, Faculty of Medicine, University of Liverpool.
  10. Prof. Jörg Oehlmann, Goethe University Frankfurt am Main, Institute for Ecology, Evolution and Diversity.
  11. Prof. Gail S. Prins, PhD, Professor of Physiology, Department of Urology, University of Illinois at Chicago.
  12. Prof. Fredrick vom Saal, Curators Professor of Biological Sciences, University of Missouri-Columbia.
  13. Prof. Pietro Giulio Signorile, President of the Italian Endometriosis Foundation.
  14. Prof. Ana M Soto, MD, Department of Anatomy and Cell Biology, Tufts University, School of Medicine.
  15. Prof. Hugh S. Taylor, M.D., Professor of Molecular, Cellular and Developmental Biology, Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University.
  16. Laura N. Vandenberg, PhD, Postdoctoral Fellow, Center for Regenerative and Developmental Biology, Tufts University.
  17. Prof. Cheryl S. Watson, PhD, Professor, Biochemistry & Molecular Biology Dept. University of Texas, Medical Branch, Galveston.
  18. Prof. Andrew Watterson, Occupational and Environmental Health Research Group, University of Stirling.
  19. Prof. R. Thomas Zoeller, Biology Department, Morrill Science Center, University of Massachusetts.

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  1. Action for Breast Cancer, Malta
  2. Alliance for Cancer Prevention, UK
  3. Arnika, Czech Republic
  4. Association for Environmental and Chronic Toxic Injury, Italy
  5. Austrian section of ISDE (International Society of Doctors for the Environment), Austria
  6. Breast Cancer Fund, USA
  7. Breast Cancer UK, UK
  8. BUND / Friends of the Earth Germany, Germany
  9. Cancer Prevention and Education Society, UK
  10. ChemSec –International Chemical Secretariat, International
  11. CHEM Trust, UK
  12. Chemical Sensitivity Network, Germany
  13. Clean Air Action Group, Hungary
  14. Comité pour le Développement Durable en Santé, France
  15. Danish Consumer Council, Denmark
  16. The Danish Ecological Council, Denmark
  17. Eco-Accord Program on Chemical Safety, Eastern Europe, Caucasus and Central Asia
  18. EcoAid, Germany
  19. Ecologistas en Acción, Spain
  20. Environmental Health Fund, USA
  21. Environment Illinois, USA
  22. European Environmental Bureau, EU
  23. Finnish Association for Nature Conservation, Finland
  24. Friends of the Earth Spain, Spain
  25. Global 2000 / Friends of the Earth Austria, Austria
  26. Health and Environmental Network, Europe
  27. Health Care Without Harm, International
  28. Indiana Toxics Action, USA
  29. Instituto Sindical de Trabajo Ambiente y Salud, Spain
  30. The Irish Doctors’ Environmental Association, Ireland
  31. Italian Endometriosis Foundation, Italy
  32. Plastic Planet, Austria
  33. Rachel’s Friends Breast Cancer Coalition, USA
  34. Réseau Environnement Santé, France
  35. Society for Sustainable Living, Czech Republic
  36. Unison, UK
  37. VHUE e.V., Germany
  38. Women in Europe for a Common Future, Europe
  39. Women’s Environmental Network, Scotland
  40. Women’s Voices for the Earth, USA
  41. WWF European Policy Office, Europe

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References

German Translation by CSN:

60 Wissenschaftler und NGOs appellieren an EFSA

Environmental Medicine: International Appeal From Würzburg

International Appeal from Wuerzburg

The European Academy for Environmental Medicine (EUROPAEM) invited many renowned national and international scientists and health care professionals to a medical conference held in Wuerzburg, Germany from April 23 to April 25, 2010. These professionals were from the fields of environmental medicine, toxicology, immunology, neurology and genetics and other health fields as well as physicians and dentist. Also in attendance were representatives of patient initiatives. The theme of this international medical conference was Science Meets Practice. It dealt specifically with the issues of Neuro- Endocrine- Immunology and their importance in environmental medicine.

Greatly concerned, participants noted the increasing prevalence of chronic multisystem illnesses such as multiple chemical sensitivity (MCS), chronic fatigue syndrome (CSF), fibromyalgia (FMS) as well as cardiovascular diseases, metabolic syndrome, neurodegenerative diseases, auto immune diseases, and cancer.

At the conference it was impressively demonstrated that these chronic diseases are based on similar pathological mechanisms. Common mechanisms are chronic inflammatory processes influenced by environmental factors including chemical pollutants, biological infectious agents, and electromagnetic field (EMF) triggers.

Chronic diseases mean long-term patients and such patients require consecutive higher medical costs. This often leads to social exclusion of the affected people. Facing the appalling reports of Europe´s growing financial constraints, especially in public health, a further increase of chronic illnesses will accelerate the ongoing collapse of the National Health Service and medical insurance companies in Europe. Remedy is only possible with a change of priorities from today´s unilaterally symptomatic oriented medicine to causally oriented medicine focusing on cost-effective primary prevention.

Conference participants addressed an urgent appeal to the European environment and health ministers, to the European Commission, the European parliamentarians, national governments and to the directors of social and private insurance companies. They urge them to take these findings and developments into serious consideration, stressing and weighting financial investments primarily in prevention, precaution and best early detection and diagnosis of these chronic and environmentally related illnesses.

All over Europe this requires the full awareness of these research findings of the practicing physicians of environmental medicine and their integration into university research and teaching. The European governments are asked to finally implement the already ratified decisions of the Fourth Ministerial Conference on Environment and Health Ministers held in Budapest in 2004.

This appeal was unanimously adopted by the congress.

Wuerzburg April 25, 2010

For the board of EUROPAEM,

Jean Huss, Vice-Chairman

Dr. Kurt Mueller, Chairman

Dr. Peter Ohnsorge, Managing Chairman

Dr. Hans-Peter Donate, Press, Responsible

International Journal of Occupational and Environmental Health Features Discovery of Asbestos-Related Pain Origin

Asbestos Mine

International Journal of Occupational and Environmental Health Features Discovery of Asbestos-Related Pain Origin from Scientists at the Karmanos Cancer Institute in Detroit 

Scientists at the Barbara Ann Karmanos Cancer Institute’s National Center for Vermiculite and Asbestos-Related Cancers (NCVAC) have discovered a probable reason for the unrelenting chest pain experienced in certain patients with asbestos-related diseases and cancers. The findings, featured in the July 20, 2009 edition of the International Journal of Occupational and Environmental Health, were published in an academic peer-reviewed manuscript by principal author Michael Harbut, M.D., MPH, co-director of the NCVAC and chief of the Center for Occupational and Environmental Medicine, affiliated with Wayne State University.  

Harbut reported the findings after studying a patient who was exposed to taconite dust as a child.  

Using a new radiography approach developed by Carmen Endress, M.D., FACR, associate professor of Radiology, Wayne State University School of Medicine and radiologist at the NCVAC, there was a documented increase in pleural plaques, causing erosion on the interior wall of the ribs. 

“This action of the pleural plaque against the covering of the bone and the bone itself is a biologically plausible and an anatomically logical explanation of the unrelenting pain which some patients experience,” said Dr. Harbut.

This new imaging approach involves enhancing images obtained on the 64-slice high resolution CT scan using the Vitrea(R) imaging software program by Vital Images. By using this imaging approach, Dr. Harbut was able to demonstrate that: 

Evidence based on the CT findings, the physical examination, pulmonary function studies, epidemiology and history of the patient’s intractable pleural pain meets the criteria for diagnosis of asbestosis. Combined with the known science of taconite dust, a link between the mine where the patient’s father worked and the patient’s disease was established.  

Due to the clarity and definition of this new imaging approach, it is more likely to detect asbestos-related diseases and cancer at an earlier stage.  

Earlier detection will allow the possibility for additional treatment options to manage the pain caused by pleural plaque beyond the narcotics often prescribed for patients with advanced stages of asbestos disease. This includes exploring other forms of traditional and nontraditional methods to control pain.  

The patient, studied since 2004 and currently 55 years of age, was exposed as a child to taconite dust unknowingly by her father, a taconite miner from 1962 – 1969, who carried the taconite dust on his work clothes. Taconite is used in the production of steel and road-patching material. It has been mined in Michigan and Minnesota. 

The patient has experienced increasing pain on her right side for the past 31 years, a persistent cough and wheezing. As the pain increased so did her medication. Using the new imaging approach, Dr. Harbut was able to show the progression of the patient’s pleural plaque over a three year period, from 2005 – 2008. The patient’s pleuritic pain, as well as the findings of her pulmonary function, physical exam and symptomology are consistent with those diagnosed with asbestosis and pleural plaques, as established by the American Thoracic Society.  

These findings also support earlier human and animal reports that dusts produced by taconite mining can evoke the same biological responses as do other fibers already defined as asbestos or asbestiform materials. 

Harbut added, “Patients often require a lifetime of narcotics to allow functioning, but we are hopeful that with this new imaging technology, more selective pain management approaches with fewer side effects can be instituted resulting in a better quality of life.”

Finally, the report supports the identification of taconite, which has not yet been categorized as asbestos but causes a disease consistent with asbestosis, and recommends a reevaluation of the definition of asbestos. This is especially important within the context of legislative efforts to prohibit the use of asbestos. 

Karmanos scientists are continuing their series of patient studies and will submit similar findings for peer review later this summer.  

In addition to Dr. Harbut, co-authors of the report include Carmen Endress, M.D., FACR; John J. Graff, Ph.D., MS, assistant professor, Wayne State University School of Medicine, and chief, Cancer Surveillance Research at the Barbara Ann Karmanos Cancer Institute; Christopher Weis, Ph.D., National Enforcement Investigations Center, United States Environmental Protection Agency; and Harvey Pass, M.D., director, New York University’s Division of Thoracic Surgery.  

About the National Center for Vermiculite and Asbestos-Related Cancers (NCVAC at Karmanos)  

In response to the United States Environmental Protection Agency’s (EPA) identification of major sources of public asbestos exposure in Michigan, and to address the need for early diagnosis and aggressive treatment of asbestos-related diseases, the Barbara Ann Karmanos Cancer Institute and the Center for Occupational and Environmental Medicine (COEM) affiliated with Wayne State University established Karmanos’ National Center for Vermiculite and Asbestos-Related Cancers. The NCVAC is co-directed by Michael Harbut, M.D., MPH, Karmanos Cancer Institute and Chief of the Center for Occupational and Environmental Medicine; and John J. Graff, Ph.D. MS, chief of Cancer Surveillance Research, Karmanos Cancer Institute and assistant professor, Department of Family Medicine and Public Health Sciences, Wayne State University School of Medicine. 

Reference: Barbara Ann Karmanos Cancer Institute, International Journal of Occupational and Environmental Health Features Discovery of Asbestos-Related Pain Origin from Scientists at the Karmanos Cancer Institute in Detroit , US Newswire, DETROIT, July 20, 2009.

 

Exposure to bitumen fumes and genotoxic effects on asphalt workers

Toxic fumes make asphalt worker sick

Bitumen fumes consist essentially of polycyclic aromatic hydrocarbons (PAHs) and their derivatives, some of which are known to be carcinogenic or cocarcinogenic in humans. The aim of this study was to investigate exposure to asphalt fumes among Turkish asphalt workers and determine whether any effects could be detected with genotoxic tests.  

The study included 26 asphalt workers and 24 control subjects. Sister chromatid exchange (SCE) and micronucleus (MN) were determined in peripheral lymphocytes. Urinary 1-hydroxypyrene (1-OHP) excretion was used as a biomarker of occupational exposure to PAHs.  

The asphalt workers had a significant increase in SCEs and MN (for each, p < 0.001). A positive correlation existed between the duration of exposure and rates of SCE or MN frequencies (r = 0.49, p < 0.05; r = 0.53, p < 0.05, respectively). The concentration of 1-OHP in urine was higher for the asphalt workers than for the controls (p < 0.001). However, we found that there was no statistically significant correlation between the urinary 1-OHP concentration and SCEs or MN frequencies (r = 0.25, p > 0.5; r = 0.17, p > 0.5, respectively).  

This study shows that Turkish asphalt workers have an increased exposure to PAHs from bitumen fumes, and genotoxic effects could be detected by SCEs and MN tests. 

Reference: Karaman A, Pirim I., Exposure to bitumen fumes and genotoxic effects on Turkish asphalt workers, Department of Medical Genetics, State Hospital, Erzurum, Turkey, Clin Toxicol (Phila). 2009 Apr;47(4):321-6.

Selenium and selenium-antagonistic elements in nutritional cancer prevention

selenium helps to prevent cancer

Selenium is an essential trace element with antioxidative, antimutagenic, antiviral and anticarcinogenic properties.  

There is increasing evidence that the dietary selenium intakes are sub-optimal in the populations of many countries and that human cancer mortalities would significantly decline if additional selenium was made available either through supplementation or the fortification of certain foods. An important property of selenium is its interaction with other elements that may be present in foods, the water, the workplace and the environment, e.g. As, Cu, Ni, Co, Cr, Mn, Zn, Cd, Sn, Pb, Hg, Bi, Mo, Ag, Au, etc.  

The sequestration of elements by selenium represents an efficient natural detoxification mechanism for some of these elements but also results in the physiological inactivation of selenium.  

Animal experiments confirm that the chronic exposure to low levels of these elements abolishes the cancer-protective effect of selenium. Human cancer is likewise significantly determined by the interactions of selenium with other elements, as evidenced by epidemiological, ecological and case-control studies. Cadmium, for example, is a key risk-increasing element for prostate cancer; for breast cancer, Cd, Cr, Zn are mainly contributing; for bronchial cancer (in smelter workers), Cd, As, Cr, Sb, Co, La, all these elements are in a reciprocal relationship with Se.  

While selenium remains the key cancer-protective trace element, the interpretation of its mode of action necessitates consideration of the effects of selenium antagonistic elements. 

Reference: Schrauzer GN., Selenium and selenium-antagonistic elements in nutritional cancer prevention, Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA, USA., Crit Rev Biotechnol. 2009;29(1):10-7