Cadmium has been linked with several human diseases including chronic kidney disease and cancer. As a carcinogen, cadmium targets several sites that are considered endocrine-sensitive, and some data suggest the breast may be among them. Although cadmium has been hypothesized to act as a metalloestrogen—a metal that triggers an estrogen-like reaction—research to date has not confirmed this as a mechanism linking cadmium and breast cancer.

Additionally, although many breast cancers are estrogen-dependent, some of the most difficult-to-treat cases are not. A new study finds that cadmium can induce malignant transformation in breast cells in vitro regardless of the absence of estrogen receptors, strengthening evidence that cadmium exposure may be a factor in breast cancer, a leading cause of cancer deaths among women [EHP 117:1847–1852; Benbrahim-Tallaa et al.].

MCF-10A cells, which are derived from normal human breast epithelium, were grown with either no cadmium exposure or continuous cadmium exposure (2.5 µM) for up to 40 weeks. Positive controls included MCF-7 human breast cancer cells (which express the estrogen receptors ER-α and ER-β) and SKBR3 breast cancer cells (which express HER2, a receptor that can be overexpressed in certain malignant breast cancer cells). In contrast, MCF-10A cells do not express ER-α, ER-β, or HER2 proteins, although expression can be acquired in carcinogenesis.

Chronic cadmium exposure of the MCF-10A cells yielded increased expression of matrix metalloproteinase-9, an enzyme that facilitates tumor cell invasion. These cells also formed cell mounds, indicating a loss of contact inhibition (the natural process of cell growth stopping once a certain density of cells is reached). When these transformed cells were implanted in mice, they formed highly aggressive tumors that demonstrated metastatic potential.

Transformed MCF-10A cells remained negative for ER-α and ER-β and also lacked HER2 protein. However, metallothionein, typically overexpressed in ER-negative breast cancers, was elevated as were several other breast cancer markers. These characteristics collectively suggest that cadmium could be a risk factor for a basal-like breast cancer phenotype, which is clinically associated with a higher risk of relapse after treatment and lower survival rates.

The precise mechanism by which cadmium may transform breast cells is unknown, but the results of this study suggest it is unlikely to be a metalloestrogenic effect via estrogen receptors. Although additional research is needed to define the mechanism, the current study provides strong evidence that cadmium may play a role in human breast cancer.

Julia R. Barrett

Julia R. Barrett, MS, ELS, a Madison, Wisconsin–based science writer and editor, has written for EHP since 1996. She is a member of the National Association of Science Writers and the Board of Editors in the Life Sciences

Dr. George J Georgiou, Ph.D.,N.D.,DSc (AM).,N.D.(P).,MSc.,BSc
Holistic Medicine Practitioner
Da Vinci Holistic Health Centre
Panayia Aimatousa 300, Aradippou 7101,Larnaca,Cyprus
Tel: (+357) 24-82 33 22
Fax: (+357) 24-82 33 21
Web: www.naturaltherapycenter.com
Web: www.collegenaturalmedicine.com
Email: admin@docgeorge.com
Author: Curing the “Incurable” with Holistic Medicine

Disclaimer: This article is not intended to provide medical advice, diagnosis, treatment, curing or preventing any type of disease or medical condition. Before beginning any type of natural, integrative or conventional treatment regime, it is advisable to seek the advice of a licensed healthcare professional. Views expressed here do not necessarily reflect those of naturaltherapycenter.com or its staff.

© 2012, Dr George J Georgiou, Larnaca, Cyprus.

Thyroid cancer incidence has been rising substantially worldwide since at least the 1970s,¹but the reasons remain murky. Trend data are scant for two other thyroid diseases, hyperthyroidism and hypothyroidism, but incidence estimates suggest each is at least 5 times more common than thyroid cancer.^2,3 Limited evidence has suggested substances such as polychlorinated biphenyls, polybrominated diphenyl ethers, bisphenol A, and triclosan may be playing a role in these disorders. Nitrate also may belong on that list of suspects, U.S. researchers now report.

The new study is apparently the first to link nitrate ingestion and thyroid cancer.

The authors found that the quartile of women who consumed drinking water containing an average concentration of nitrate–nitrogen⁵ (NO₃–N) greater than 2.46 mg/L—about one-fourth the EPA maximum contaminant level of 10 mg/L—were 2.18 times more likely to have thyroid cancer than the bottom quartile, whose water contained less than 0.36 mg/L NO₃–N. Consuming water containing more than 5 mg/L NO₃–N for more than five years increased the risk slightly more. The women in the highest quartile of daily nitrate ingestion from food were 2.9 times more likely to have thyroid cancer than the quartile who consumed the least, and were 24% more likely to report having hypothyroidism. Nitrate in food dominated total nitrate intake.

The study was based on records from women who were followed from 1986 to 2004 as part of the larger Iowa Women’s Health study. The women were 55–69 years old at recruitment. The researchers had extensive self-reported demographic, behavioral, and medical data, but fewer data on overall diet and none on nitrate levels in individuals. Instead, they had to develop intake estimates based on local public water supply monitoring data and national food nitrate data. The small number of thyroid cancers—40 in the approximately 21,000 women analyzed—also is a limitation, although the findings were statistically significant.⁶

The numerous limitations make Lewis Braverman, a professor of medicine at the Boston University School of Medicine, somewhat skeptical of the conclusions. “The evidence is fairly soft,” he says. He notes, though, there has been some evidence globally of a nitrate-related association with hypothyroidism, goiter, and other thyroid disorders in subjects such as pregnant women and children exposed to far higher nitrate concentrations than those reported in the present study.⁷ Ongoing and planned studies, including one looking at men, may provide additional clues, says Mary Ward, lead author of the current study and a senior investigator at the National Cancer Institute.

Thyroid cancer is estimated to be the seventh leading site of new cancers in U.S. women, according to the American Cancer Society.⁸ Incidence is about three times higher in women than in men, similar to the pattern worldwide.¹ Some experts are concluding that increased detection alone is not likely to be responsible for global increases.⁹

Synthetic fertilizer can be an important source of nitrate in water and food.¹⁰ The foods that often have the highest concentrations of nitrate, such as spinach, kale, and beets, often are touted for their nutritional benefits. The women in this study who were hardest hit by thyroid disorders tended to be better educated, physically active nonsmokers—a group Ward says is more likely to eat vegetables.

1. 1. Kilfoy BA, et al. Cancer Causes Control 20(5):525–531. 2009. FIND THIS ARTICLE ONLINE
2. 2. Michalek AM, et al. J Fam Pract 49(7):638–640. 2000. FIND THIS ARTICLE ONLINE
3. 3. Emiliano AB, et al. J Cin Endocrinol Metab 95(5):2227–2233. 2010. FIND THIS ARTICLE ONLINE
4. 4. Ward MH, et al. Epidemiology 21(3):389–395. 2010. FIND THIS ARTICLE ONLINE
5. 5. The term “nitrate-nitrogen” (NO3–N) refers to the total nitrogen present in the form of the nitrate ion. This differentiates it from nitrite–nitrogen (NO2–N) or ammonia–nitrogen (NH3–N).
6. 6. The 19-year span of the study and the changing accuracy and diagnostic patterns for thyroid cancer make it difficult to say how this incidence compares with national rates. But for one perspective, the American Cancer Society estimated 17,640 new thyroid cancers were diagnosed in U.S. women aged 75–90 in 2004, the year data collection for this study ended and the approximate age range for the women at that time. According to the U.S. Census Bureau, the U.S. female population for that age range was 9.8 million in 2004. That equates to 0.18% of the larger population of women aged 75–90 having thyroid cancer, compared with 0.20% in the current study.
7. 7. For instance, Gatseva Penka and Argirova [Int J Hyg Environ Health 211(5–6):555–559 (2008)] showed high nitrate levels in drinking water may be a risk factor for thyroid dysfunction in rural Bulgarian children and pregnant women, and Rádiková et al. [Thyroid 18(3):353–362 (2008)] demonstrated possible thyroid effects of nitrates and organochlorines in highly polluted areas of Slovakia.
8. 8. ACSCancer Facts & Figures 2009. Atlanta, GA: American Cancer Society (2009).
9. 9. For instance, Enewold L, et al. Cancer Epidemiol Biomarkers Prev 18:784–791 (2009).
10. 10. European Union Scientific Panel ESPA J 689:1–79. 2008. FIND THIS ARTICLE ONLINE

Bob Weinhold

Bob Weinhold, MA, has covered environmental health issues for numerous outlets since 1996. He is a member of the Society of Environmental Journalists. Taken from Environmental Health Perspectives.

Dr. George J Georgiou, Ph.D.,N.D.,DSc (AM).,N.D.(P).,MSc.,BSc
Holistic Medicine Practitioner
Da Vinci Holistic Health Centre
Panayia Aimatousa 300, Aradippou 7101,Larnaca,Cyprus
Tel: (+357) 24-82 33 22
Fax: (+357) 24-82 33 21
Web: www.naturaltherapycenter.com
Web: www.collegenaturalmedicine.com
Email: admin@docgeorge.com
Author: Curing the “Incurable” with Holistic Medicine

Disclaimer: This article is not intended to provide medical advice, diagnosis, treatment, curing or preventing any type of disease or medical condition. Before beginning any type of natural, integrative or conventional treatment regime, it is advisable to seek the advice of a licensed healthcare professional. Views expressed here do not necessarily reflect those of naturaltherapycenter.com or its staff.

© 2012, Dr George J Georgiou, Larnaca, Cyprus.

In its new report, Reducing Environmental Cancer Risk: What We Can Do Now, the President’s Cancer Panel (PCP) for the first time highlights the contribution of environmental contaminants to the development of cancer.¹ The panel also points out the great need for increased research on environmental risk factors. In a letter to the President that prefaces the report, the panel wrote that “the true burden of environmentally induced cancer has been grossly underestimated.”

The PCP was established in 1971 by the National Cancer Act, the first salvo in former President Nixon’s “war on cancer.” The panel annually reports to the president on the activities of the National Cancer Program, which Jennifer Burt, special assistant to the PCP, describes as “anything that has to do with cancer in the United States.” Current panelists are Margaret Kripke of the University of Texas MD Anderson Cancer Center and LaSalle D. Leffall of Howard University College of Medicine, both appointed by George W. Bush; an open third position awaits appointment by the Obama administration, Burt says.

Past PCP reports have focused on the contribution of lifestyle to cancer, but Kripke says those reports were criticized for not reviewing the contribution of environmental exposures. The panel therefore chose to dedicate this report to environmental risk factors. In developing the report, the panel reviewed more than 400 scientific reports and heard testimony from 45 invited experts at four public meetings.

The report outlines research on consumer products, combustion by-products, and agricultural chemicals used in residential and commercial landscaping. It highlights cancer attributable to radiation and points out that military activities and unnecessary medical X rays are sources of exposure that can increase cancer risk, especially among children.

Although 60% of U.S. cancer deaths are attributed to lifestyle factors such as smoking, lack of exercise, and poor diet,² the factors contributing to the remaining 40% are a mystery, Kripke says. But the panel did not attempt to characterize the percentage of cancers that might be linked to environmental exposures. “We don’t have any real idea of the contribution of environmental factors to human cancer,” Kripke says. The report points out that most cancer research focuses on genetic and molecular mechanisms behind the disease.¹

Several environmental scientists were relieved to see the report take such an honest tone about the need for research. “They really point out where we have huge gaps of data,” says Deborah Swackhamer, a professor of environmental chemistry at the University of Minnesota and chair of the U.S. Environmental Protection Agency’s independent Science Advisory Board. “I think the science they used to back up the report is very mainstream,” she adds.

The American Cancer Society (ACS) agrees with 85−90% of the panel’s report, says Otis Brawley, ACS chief medical officer. Yet Brawley and other cancer researchers fear the emphasis on environmental factors may divert the general public from making positive lifestyle changes at a time when an estimated 41% of Americans will develop cancer during their lives and 21% will die of the disease.³Michael J. Thun, vice president emeritus of epidemiology and surveillance research for the ACS, says, “It would be unfortunate if the effect of this report were to trivialize the importance of other modifiable risk factors that, at present, offer the greatest opportunity in preventing cancer.”⁴

1. Reuben SH. Reducing Environmental Cancer Risk: What We Can Do Now: 2008–2009 Annual Report, President’s Cancer Panel. Bethesda, MD:National Cancer Institute (2010).
2. 2. Reuben SH. Promoting Healthy Lifestyles: Policy, Program, and Personal Recommendations for Reducing Cancer Risk: 2006–2007 Annual Report, President’s Cancer Panel. Bethesda, MD:National Cancer Institute.
3. 3. Horner JM, et al., eds. SEER Cancer Statistics Review, 1975–2006 [Internet]. Bethesda, MD:National Cancer Institute; based on November 2008 SEER data submission, posted to the SEER Web site, 2009 [cited 2009 Jul 19]. Available: http://seer.cancer.gov/csr/1975_2006/.
4. 4. Sampson D. 2010. Cancer and the environment [blog entry]. 6 May 2010. Available:http://acspressroom.wordpress.com/2010/0​5/06/cancer-and-the-environment/ [accessed 13 July 2010].

Catherine M. Cooney

Catherine M. Cooney, a science writer in Washington, DC, has written for Environmental Science & Technology and Chemical Watch.

Dr. George J Georgiou, Ph.D.,N.D.,DSc (AM).,N.D.(P).,MSc.,BSc
Holistic Medicine Practitioner
Da Vinci Holistic Health Centre
Panayia Aimatousa 300, Aradippou 7101,Larnaca,Cyprus
Tel: (+357) 24-82 33 22
Fax: (+357) 24-82 33 21
Web: www.naturaltherapycenter.com
Web: www.collegenaturalmedicine.com
Email: admin@docgeorge.com
Author: Curing the “Incurable” with Holistic Medicine

Disclaimer: This article is not intended to provide medical advice, diagnosis, treatment, curing or preventing any type of disease or medical condition. Before beginning any type of natural, integrative or conventional treatment regime, it is advisable to seek the advice of a licensed healthcare professional. Views expressed here do not necessarily reflect those of naturaltherapycenter.com or its staff.

© 2012, Dr George J Georgiou, Larnaca, Cyprus.