However, researchers studying p53 function in fruit flies, and reporting in Current Biology, Vol. 15, 2063-2068, November 22, 2005, have shown new evidence that despite the protective role of p53 as a guardian against tumor formation, normal levels of p53 activity--at least in some cell types--may indeed contribute to aging and decreased lifespan.

The researchers investigated the role of p53 in aging by observing the effects of disrupting this protein in the neurons of adult fruit flies. They found that expression of a so-called "dominant-negative" version of p53--that is, a disfunctional version of the protein that inhibits the activity of normal p53--extended flies' life span and increased their ability to withstand gene-damaging stress. The authors found that this disruption of p53 did not further increase the lifespan of flies on a calorie-restricted diet, suggesting that decreased p53 activity and calorie restriction may influence lifespan through a common molecular mechanism.

Because neurons are less prone to tumor formation than other cell types, and because disruption of p53 activity in neurons was sufficient to extend lifespan in the fruit fly, the new findings suggest that by attending to p53 activity in different cell types, it may be possible to take therapeutic advantage of p53's tumor-preventing activity while avoiding its unwanted negative effects on lifespan.

And that is the direction that will result in more patients suffering less, and living longer. ( It has long been recognized that every person with cancer is markedly different from other patients.)

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