The U.S. Department of Health and Human Services recently released its “14th Report on Carcinogens.”
The department has added 7 more known human carcinogens to the list, bringing the total up to 248.
While one might expect industrial solvents used to make hydrofluorocarbon chemicals, such as trichloroethylene (TCE) to make the list, which it did, the other additions might come as a surprise.
They’re not necessarily the first thing that comes to mind when you think of carcinogens.
Read on to discover what these new threats are, and what you can do to protect yourself.
In addition to the chemical TCE, the department classified “cobalt and cobalt compounds that release cobalt ions in vivo” as “reasonably anticipated to be a human carcinogen,” based on evidence gathered through animal experiments.(1)
Cobalt is a naturally occurring metal used most often in creating metal alloys used in military and industrial metals. Unless you work with metal or have had problems with cobalt alloy surgical implants, you don’t have much to worry about.
The other five carcinogens, on the other hand, are all viruses…
Now, we’ve known for years that all kinds of viruses can lead to cancer, so this isn’t necessarily shocking news…
In fact, according to a 2007 report published in the journal Yale Journal of Biology and Medicine, viruses cause an estimated 15% of all human cancers worldwide.(2)
Viruses initially take hold in the body by entering living cells and “hijack” their functioning to make more viruses. Some do this by inserting their own DNA or RNA into the host cell.
Once this happens, it can push the cell to become ever more mutated and unstable. This can eventually cause the cell to become cancerous.
But not every virus attacks every cell. Below are the five new viruses now classified as carcinogens, and how they affect the body.
Epstein-Barr virus (EBV)
Epstein-Barr virus (EBV) is a herpes virus that’s usually transmitted by saliva or bodily fluids. About 90% of adults worldwide carry it.(3) Many people live with EBV and show no symptoms or have complications from it.
However… human, clinical and molecular studies show EBV can lead to four types of lymphoma, cancer that starts in lymph nodes, spleen, thymus, bone marrow or other cells known as lymphocytes. The four types are
- Immune-suppression-related non-Hodgkin and
- Nasal type extranodal NK/T-cell lymphoma
It’s also present in many cases of prostate cancer (see Issue #232).
Researchers believe EBV can lead to lymphoma and epithelial cancer (of the tissue that lines the surfaces of blood vessels and organs throughout the body, such as some types of stomach cancer) because it weakens the immune system over time.
A weakened immune system can lead to the production of cancer-causing viral proteins. To make matters worse, your immune system, once weakened, isn’t able to effectively stop cells from mutating and spreading uncontrollably, the hallmark of cancer.
These potential causes are in addition to an individual’s diet, genetic susceptibility and make-up, which also influence cancer development.
Kaposi sarcoma-associated herpesvirus (KSHV)
Another strain of herpesvirus, similar to EBV, is Kaposi sarcoma-associated herpesvirus (KSHV).
It’s transmitted through saliva, sexual contact, contaminated organ transplants and/or blood transfusions. Like EBV, people can carry the virus and live totally normal, healthy lives.
KSHV causes cancer primarily in people with suppressed immune systems. The virus transforms proteins and RNA in the host cells into cancer cells, and then works to promote their growth.
Research shows that approximately 90% of Kaposi sarcoma patients carry KSHV, and more than 100 human studies have shown a link between KSHV infection and Kaposi sarcoma.(4)
Merkel cell polyomavirus (MCV)
Merkel cell polyomavirus (MCV) was discovered in 2008 and researchers are still trying to understand how it spreads.
It usually infects the skin, and healthy people continually shed infected cells, releasing them into the environment.
Clinical, epidemiological and molecular studies show that MCV causes Merkel cell carcinoma, a rare and aggressive skin cancer, by integrating the viral DNA into the host cell and by expressing two MCV proteins. Only this mutated, integrated form of MCV leads to cancer.(5)
When Merkel cell carcinoma does occur, it’s usually in white elderly males and people with weakened immune systems.(6)
It usually starts as a single, painless, purple or bluish-colored lump on sun exposed skin. To help protect yourself from MCV and Merkel cell carcinoma
- Practice good hygiene;
- Protect your skin from natural and artificial sunlight; and
- Monitor your skin and consult a dermatologist if you notice changes.
Human T-cell lymphotropic virus type 1 (HTLV-1)
Human T-cell lymphotropic virus type 1 (HTLV-1) is spread through contact such as breastfeeding, sharing needles, infected organ transplants and sexual contact. Many people who carry this virus remain healthy and show no symptoms.
Multiple human studies show a link between HTLV-1 and adult T-cell leukemia/lymphoma (ATLL). ATLL is a rare cancer that infects the body’s T cells, specifically white blood cells known as CD4 T cells, which help to fight off infection.
Over 90% of all people who develop ATLL are infected with HTLV-1. The virus integrates itself into the genome of host cells and alters the DNA, producing cancer-causing viral proteins.
According to the U.S. Department of Health and Human Services, about 90,000 people in the United States are infected with HTLV-1, but only a very small number of them ever develop virus-related cancer.(7)
Again, the health of a person’s immune system plays a role in whether or not they develop ATLL or carry HTLV-1 without symptoms to the end of their days.
To reduce the risk of contracting HTLV-1, practice safer sex. Women who are infected should avoid breastfeeding.
Human immunodeficiency virus type 1 (HIV-1)
Approximately 1.2 million people in the United States carry human immunodeficiency virus type 1 (HIV-1). It’s transmitted through blood, sexual contact, during pregnancy from mother to child and through breastfeeding.
HIV-1, when left untreated, can lead to acquired immune deficiency syndrome (AIDS). There’s also significant human evidence that it can lead to several different types of cancer, including
- Kaposi sarcoma
- Non-Hodgkin and Hodgkin lymphoma
- Cervical, anal and vaginal cancer
- Conjunctival eye cancer
- Non-melanoma skin cancer
Numerous studies in different populations provide evidence that people with HIV-1 have a higher risk for these cancers compared to uninfected people of the same age.(8)
Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer are considered AIDS-defining cancers. A diagnosis of any of these three cancers means the HIV infection has progressed to AIDS.(9)
Researchers believe it’s not necessarily HIV-1 that mutates cells and leads to cancer, but rather the weakening of the immune system together with other cancer-causing viruses. Because the body is already unable to defend itself, cancer cells have a better chance of taking hold and multiplying.
However, a person carrying HIV-1 can receive treatments such as highly antiretroviral therapy (HAART) and combination antiretroviral therapy (cART). These treatments reduce the level of HIV-1 in the blood and can substantially lower the risk of developing Kaposi sarcoma and non-Hodgkin lymphoma.
The best ways to reduce your risk of HIV-1 infection are to practice safer sex and do not share needles with another person.
While news of more cancer-causing viruses may sound dire, there’s actually a silver lining.
Medical professionals, researchers and scientists already know a lot about viruses… more than they know about cancer…
This means that by applying the body of knowledge already amassed about viruses, we may be able to apply it to cancer research to more quickly develop effective treatments for certain kinds of cancer.
In the meantime, the best “cure for cancer” is still prevention. So do what you can to prevent viral infections and stay healthy with a whole foods diet and plenty of exercise.
- Cobalt and cobalt compounds that release cobalt ions in vivo. http://ntp.niehs.nih.gov/ntp/roc/content/profiles/cobalt_ions.pdf
- Viruses and human cancer. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1994798/
- Epstein-Barr virus (EBV). http://www.niehs.nih.gov/health/materials/5_viruses_508.pdf
- Kaposi sarcoma-associated herpesvirus. http://ntp.niehs.nih.gov/ntp/roc/content profiles/viruses_kshv.pdf
- Merkel cell polyomavirus. http://ntp.niehs.nih.gov/ntp/roc/content/profiles/viruses_mcv.pdf
- Merkel cell polyomavirus (MCV). http://www.niehs.nih.gov/health/materials/5_viruses_508.pdf
- Human T-cell lymphotropic virus type 1 (HTLV-1). http://www.niehs.nih.gov/health/materials/5_viruses_508.pdf
- Human immunodeficiency virus type 1. http://ntp.niehs.nih.gov/ntp/roc/content/profiles/viruses_hiv.pdf
- Human immunodeficiency virus type 1 (HIV-1). http://www.niehs.nih.gov/health/materials/5_viruses_508.pdf