Following up on my last post on cancer research, I thought I'd point out a release illustrative of the search for keys to cancer - and the ongoing process of evaluating whether it is even sensible to be searching for such keys. By "keys" I again mean some sort of common mechanism, or small number of common mechanisms, by which all (or even almost all) cancer could be prevented or successfully treated with the technology of the next decade - if only we knew these keys existed.

Most types of cancer are believed to begin with a random genetic mutation that makes a normal cell go horribly awry. This is followed by mutations, which endow the cancer cells with properties allowing them to grow without normal controls to become a tumor. These mutated genes would be targets for chemotherapy.

But Loeb had another idea that he originally hatched many years ago – what if the cancer cells changed somehow, and became much more likely to mutate? These "mutator" cells would develop dangerous genetic mutations at a much faster rate than normal cells, which might account for the high number of mutations seen in tumor cells.

Since the technology of cancer genetics has dramatically improved, Loeb and his colleagues have only recently been able to test this hypothesis. They found that tumor tissue had random mutation rates up to 100 times higher than normal tissue from the same patient. The "mutator" hypothesis seems to be correct.

Now for the bad news: if cancer cells do indeed become "mutator" cells, traditional chemotherapy and other drugs may never be very effective against advanced tumors.

...

Loeb’s work may also lead to a discovery of why cancer cells are becoming mutator cells. If scientists understand what happens in a cancer cell that makes it become a mutator, they might be able to prevent that from happening in other cells, or slow down the mutation rate.

"The idea is that if you might normally get exposed to something in the environment at 20 years old that would give you cancer by age 55, then if we cut the mutation rate in half, you might not get cancer until age 90, and you may even die of something else before that," Loeb explained.

You might recall a similar look at a potential root cause leading to greatly increased rates of mutation was mentioned a little while back at the Longevity Meme:

When the teams compared patterns of gene activity in stem cells from healthy and cancerous tissue they found that those from cancers were often locked in a state in which they carry on multiplying as primitive stem cells, instead of maturing into specific tissues. ... When they're in this state they divide more, and in the process may accumulate additional mutations which ultimately turn them cancerous.

What are the real roots of cancer? Do the keys to cancer exist in a form that we can find and take advantage of within the next decade or two? Can researchers produce global anti-cancer technologies dramatically better than the development of an effective therapy, one type of cancer at a time? Stay tuned.

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Posted by Reason at February 20, 2007 9:32 PM | TrackBack (0)