When most cancer survivors ask their oncologists if they can get a tattoo, the answer is, "No! And don't even think about it." The reason often stems from numerous studies looking at a possible connection between tattoos and leukemia, a blood cancer. The big concern is chemicals in the dye that will go directly on and potentially in the skin. The key questions many studies are trying to answer right now are: "What are in the dyes?" "Do they go directly into the blood stream for some or all?" "What is the impact of the dyes long-term?" and "Why are those dyes not regulated in he first place?"

So if everything else that can potentially go into your bloodstream is regulated, then why isn't tattoo ink?

First, to give you perspective, I have to share one cautionary rule that many oncologists tell survivors to follow in order to lower their risk, and this is certainly good for anyone. Think before you apply anything to your skin because it does have the potential to go directly into your bloodstream, and that includes sunscreen, bug spray or lotion. This should come as no surprise, especially with the existence of a birth control patch the size of a bandage that goes directly into your bloodstream. So if everything else that can potentially go into your bloodstream is regulated, why isn't tattoo ink?

The Food and Drug Administration (FDA) states on its website, "While state and local authorities oversee the practice of tattooing, ink and ink colorings (pigments) used in tattoos are subject to FDA regulation as cosmetics and color additives. However, because of other public health priorities and a previous lack of evidence of safety concerns, FDA has not traditionally regulated tattoo inks or the pigments used in them." After receiving various reports of adverse reactions to tattoo ink, the FDA launched an investigation in 2008. It has a warning on its website to consumers that says several of the pigments used in tattoo ink are "industrial-grade colors suitable for printers' ink or automobile paint."

The FDA's National Center for Toxicological Research (NCTR), research chemist Paul Howard, Ph.D., and his team are investigating to get more answers. What they do know is that some ink particles have shown the ability to go beyond the skin, into the bloodstream and into the lymph nodes or lymphatic system, which is where the body carries out disease-causing organisms. That's a problem. The FDA also found some potentially dangerous substances, including metals and hydrocarbons that are known carcinogens in the ink, saying, "One chemical commonly used to make black ink called benzo(a)pryrene is known to be a potent carcinogen that causes skin cancer in animal tests."

Some ink particles have shown the ability to go beyond the skin, into the bloodstream and into the lymph nodes or lymphatic system, which is where the body carries out disease-causing organisms.

Outside the US, more studies are being conducted. One out of the University of Bradford in the UK found that the tattoo process removes the body's main connective tissue and the ink particles leave the surface of the skin and travel elsewhere. Another study out of the UK is led by Jorgen Serup, a professor of dermatology at Copenhagen's Bispebjerg University Hospital. He claims that he found evidence that the nanoparticles present in inks can reach major organs of the body and cause cancer. According to the International Business Times, the study says that as many as 13 out of 21 commonly used European inks have cancer causing chemicals in them. The article goes on to state that the Tattoo Ink Manufacturers of Europe "believe that about 5 percent of European tattooists use toxic ink, and wants the EU to compel ink makers to conduct risk assessments on their products and make the results public."

Think that henna tattoos might be your best shot? Think again! The Telegraph looked at a study in the United Arab Emirates, published in the "Leukemia and Lymphoma Journal." Women there who use henna to stain their nails, hands, feet, etc., face a higher incidence of leukemia. They said it is not the henna itself that is the problem but rather the compounds used as a solvent for the henna powder. That solvent contains benzene, which is known to cause cancer. According to the Telegraph, benzene is banned in many countries but still used.

I checked many tattoo website across the country to see if, perhaps, a newer, "cleaner" dye has been introduced since these studies were published, but I found no mention of anything. A few sites mentioned that there are always risks since it is a dye/pigment is permanently being added to the layers of your skin. Bottom line: There is no hard evidence that there is a 100 percent connection to leukemia but there is much cause for concern about what chemicals are in the ink, the long-term effects of the ink, and how the ink enters the body. Ask questions. Know before you ink. Perhaps, if you have a history of cancer in your family and you are at higher risk, talk to your doctor as well.