Sunbeds as Carcinogens

Finally some sense has been made about the use of tanning beds. A study by cancer researchers supported by the World Health Organization have determined that the use of tanning beds before the age of 30 increases the risk of developing skin cancer, specifically the deadly form melanoma, by 75%. Although the tanning bed industry has for the most part denied any link between tanning beds and increased rates of skin cancer - from a genetic point of view, it was only a matter of time until the evidence supported what we already knew: Lying inside a metal coffin and being bombarded by radiation is bad for your health.

The bottom line is that UV radiation, in all wavelengths, damages DNA to some degree. Some forms of UV are worse than others, but no wavelength is DNA "friendly". To put it bluntly, UV radiation fries DNA. More scientifically, UV radiation causes small breaks in the DNA molecule and the formation of a chemical structure called a thymine dimer. Thymine dimers represent a special challenge for our DNA repair mechanisms, and although our cells have evolved mechanisms to repair these structures, the changes that the repair generates an unintended detrimental mutation is high. If this mutation occurs in a gene that is responsible for regulating cell growth (or maybe even mitochondria now?), the result can be an out-of-control cell - commonly called cancer.


Of course, the head of the The Sunbed Association disputes the claim, stating that there is no link between responsible use of sunbeds and cancer. Seems like similar statements were made in the 1970s and 1980s with regards to cigarettes. I imagine that the debate will now focus on what constitutes "responsible". But according to this study, the only responsible use would be to lie down in the tanning bed and not turn on the UV light. Anything else is simply inviting an increased risk of death.

For more info - see this article in USAToday

A New Twist in Understanding Cell Division.

Pop Quiz: What is the role of the mitochondria in a cell?

1. digest incoming food particles
2. store DNA
3. produce ATP
4. regulate the cell cycle
   

Until just a few days ago, the only correct answer to this question would have been #3. The mitochondria of a cell are well recognized as the powerhouses of the cell. They are the location where energy-rich nutrients such as carbohydrates and fats are brought in and "burned"in the presence of oxygen to produce the energy (in the form of ATP) to power our cells. It is one of the earliest lessons of any introductory biology course.

However, in a development that is sure to change the way we look at cell biology, it now appears that answer #4 also may be correct. A group of researchers at the National Institutes of Health reported in the July 21, 2009 issue of PNAS that the fusion of the the mitochondria in a cell influences the buildup of a protein called cyclin. This in turn, acts as a control mechanism for the cell to bypass an important checkpoint (G1/S), allowing the cell to divide.

Cyclin is a form of protein "clock" within a cell. Its job is relatively simple, as cyclin levels accumulate in the cell, it overcomes a series of thresholds that tell the cell to undergo important activities. One of these activities is the cell cycle. The cell cycle is a type of cell "day". At specific points in the cycle the cell undergoes DNA replication and specific activities to prepare for cell division. These activities are regulated by special proteins called checkpoint proteins. You should be very interested in these checkpoint proteins - their job is to ensure that the cell does not divide unless it needs to, since unrestricted cell growth is called cancer. There are two specific classes of these proteins, proto-oncogenes and tumor supressor genes. Until earlier this week, they were the primary focus of most research dedicated to understanding the cell cycle.

What the NIH team reported is that just prior to one of these checkpoints (G1/S) is that the mitochondria form an unusual tubular network in the cell. The images from their paper show a network of mitochodnria that is reminiscent of a map of a subway line in a major city. The authors then show that the presence of this network is correlated to a increase in a form of cyclin that is known to be a major key in overcoming the G1/S checkpoint, allowing the cell to duplicate its DNA in preparation for cell division.

Why should we be interested in this? First of all, because it demonstrates that by looking in unconventional areas, we can find new clues as to how cell function. Until earlier this week, no one would have answered #4 in the above quiz. But more importantly, scientists who study cancer genetics and biochemistry can now look for relationships between these mitochondria and unregulated cell growth, which should, eventually, lead to new insights on how to battle some forms of cancer.

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Click here to access the article in PNAS

Advances in Cancer.... Linking the Pieces

As part of the Darwin Bicentennial Lecture Series at Appalachian State University, Dr. Paul Ewald, author of Plague Time: The New Germ Theory of Disease, recently gave a presentation on the genetic basis of cancer. During the lecture, Dr Ewald spent a considerable amount of time discussing the role of infectious agents, specifically viruses, as the causative agents of cancer. Specifically, Dr Ewald talked about the human papillomavirus (HPV), and how screening of seemingly unrelated cancers, such as breast cancer and cancers of the head and neck, are linking this virus as a potentially more important agent in cancer formation than previously thought.

If infectious agents are responsible for priming cells to enter into a tumor-forming stage, as Dr Ewald's work strongly suggests, then the use of vaccines against these agents could be a major advance in the evolution of preventative strategies against cancer. HPV vaccines are already recommended for young women to prevent against cervical cancer later in life. Now it appears that these vaccines may have potential benefits in other areas as well.

Interestingly, a recent article in Science Daily (Genetic Markers for Aggressive Head and Neck Cancers) presents data from a study at the Albert Einstein College of Medicine that a specific type of genetic markers, called microRNAs, may be used to identify individuals who are highly susceptible to forms of head and neck cancer. The researchers in this study propose that genetic screening may be useful in the development of new treatments for these cancers.

Is is possible that the microRNA markers identified by the team at the Albert Einstein College of Medicine are actually indicating susceptibility to the HPV virus? We know that everyone who carries HPV does not necessarily develop cancer, but the reason why is not yet clear. It could be that a genetic susceptibility is the key. Certain genetic combinations could promote HPV influence, and result in the formation of the cancer phenotype. If this is the case, then trials of using the HPV vaccine on individuals who have these specific microRNA markers are definitely in order. This could provide some very useful insights on new treatments of specific types of cancers, specifically those that have been identified to be associated with an infectious agent.

The Verdict on Autism

Finally we can get down to some real issues regarding autism. As reported in this editorial in the Los Angeles Times, the US Court of Federal Claims has found no substantiated link between autism and the MMR vaccine or the vaccine additive thimerosal.

I have covered autism in two previous posts "The Question of Fragile X " (9/27/2008) and "Autism in the News " (4/4/2008). In both cases I have discussed some of the genetics behind this disease. For example Scientists know that autism is a multifactorial trait - meaning that it probably has both a genetic and environmental component. It is also most likely that autism is a disease that displays genetic heterogenity - meaning that it is actually several different diseases that express themselves the same way. Cancer is a good example of a disease with genetic heterogeneity - just because you get cancer does not mean that it is from the same cause.

Should we have never investigated the MMR vaccine or thimerosol? - of course not. It is always important for scientists to follow-up any leads as to a cause of a complex disease such as autism. However, numerous studies have indicated that the link between these and autism is almost insignificant. So why is this an issue? For too long the research community has been having to focus on only one cause - vaccines and their additives. This focus on one factor is not resource-friendly and it distracts from the search for a real cure. The results are in - time to move on.

There will be those individuals who accuse the government, CDC, and pharmaceuticals of a massive cover-up. Others will decide not to vaccinate their kids based on religious preferences. Neither of these two groups should be treated seriously since 1) our government is not smart enough to cover-up the simplest lie, and 2) the consequences of not being vaccinated far, far outweigh the risks.

We need to support autism research, even when the results do not match what we want. That is what science is all about.

Want more information - check out the National Institutes for Health pages on autism and the National Autistic Society page on autism genetics.

Cell Phones and Cancer - Round X

As reported on CNN (Cancer expert warns employees on cell phones, 7/23/2008), Dr Herberman, director of the University of Pittsburgh Cancer Institute, has advised against the use of cell phones by employees, citing that it may possibly cause cancer. Here we go again.....

This type of grandstanding by a official should not be tolerated by the academic, medical or scientific communities. It does nothing but confuse the general public and further degrade the reports of legitimate scientists (which Dr. Herberman is suppose to represent!). Reports like this one often go viral over the web, and most often get distorted in many ways. I predict that the National Enquirer will soon start to blame all of the celebrity problems in the news on the use of cell phones. If I was on the staff of this Institute, I would be asking some tough questions of my leadership.

Is it possible that the use of cell phones may increase the risk of certain types of cancer? There is always a possibility - even though multiple published reports have discounted this idea. There may be physiological and genetic factors that predispose some individuals to certain forms of cancer, and these people may use cell phones, but that does not really mean that the cell phone caused the cancer. Should additional studies be performed? ..... maybe, especially if it covers some area of study that has been neglected in a previous study, including the effects on youn brains. Herberman contends that we can't wait for the scientific process to examine the link..... and he is the head of a major scientific cancer institute? Something doesn't sound right.

I wonder if Dr Herberman drives to work in a car..... after all, we know for certain that cars kill over 40,000 Americans per year, and that the emissions from automobiles are killing additional thousands per year (as reported by the World Health Organization)....but I don't hear any outcry about that from Dr Herberman.

For a more detailed report - see the AP report "Pittsburgh cancer center warns of cell phone risks"