Wednesday, April 29, 2009

the amazing complexity of life

When people learn that I’m a geneticist, often the question of what I do specifically or what I want to do will come up. And often, I’ll get some sort of query as to whether or not I’ll go searching for the cure to cancer.

What I don’t get is why so many people seem to be under the misconception that cancer can have a single cure when there are so many causes of cancer. There are limitless ways for a person to develop cancer, all of which in the end come back to some kind of malfunction in that precious guide to life, DNA.

Each one of your individual cells carries within this acidic molecule instructions for how to metabolize, how to heal wounds, how to eliminate invaders, and, most importantly to this discussion, how to divide and grow- and also how to stop dividing. Cell division is imperative for life as we know it. Your skin cells divide constantly just to keep up with the outer layer that’s constantly being removed. And let’s not even start on what your poor stomach lining cells go through. They live in a very hostile environment with an extremely acidic pH. The key to their survival is that they don’t survive very long- just a short existence mostly marked by their furious division to keep up with the decaying effects of the stomach acid. So, new cell division is a major part of what keeps us functioning correctly.

But as important as this division is, there are an amazing number of genes in your DNA that are dedicated to the sole purpose of making sure the cell doesn’t divide too often or if it’s not ready. These gene products act as checks before giving the okay for the cell to go ahead and complete cell division and telophase. They make sure that it is necessary for the cell to divide, and also that there aren’t major problems within the cell that will cause more problems in the daughter cells. These genes are crucial to balanced growth. And if they get damaged, the result is usually uncontrolled cell growth, or what we commonly call cancer.

Because really all that cancer is is the unchecked division of cells. The cancerous cells consume precious energy that could be going to maintaining a healthy system elsewhere and disrupt the functions of the organs or systems that they are growing in. This is why cancers almost always form in body systems that are actively growing; no one ever hears about nerve cancer because the nervous system in an adult has ceased to undergo cell division. Cancer is much more likely to take root where cell division is active- the colon, the stomach, and especially the reproductive organs, where cell division is constantly taking place. And, as I mentioned, there are numerous genes checking the growth of these cells. If any one of these genes are damaged, or even if a gene that controls the expression of one of these genes is damaged, the result will almost invariably be cancer. Molecular biologists like to say that anyone who lives long enough will without fail contract some kind of cancer, and this is largely true. Througout the course of our lives, we pick up mutations and deletions and other alterations to our DNA in different cells throughout our bodies. Most of these are harmless and have no consequences. But once a mutation hits a critical gene, cancer is the result.

And this is a big piece of why it’s impssoble to come up with one simple one-size-fits-all cure for cancer- things that are caused from different sources need different treatments, even if the symptoms are the same. There’s a lot more to it than that, but it’s a point that most people don’t seem to realize.

2 comments:

Josh said...

You might appreciate this: http://www.phdcomics.com/comics/archive.php?comicid=1162

Courtney_and_John said...

Everyone asks me if I am going to cure cancer too. I just smile and say that I work on plants but then they want me to tell them what is wrong with their yard - you can't win!