P53, APOPTOSIS, CANCER, AND BABUSHKA DOLLS

In a taverna in the old city of Rhodes

We ate a kilo of fresh-caught shrimp, washed down with water (Linda) and retsina (me).

The significance of the pink elephant is lost forever.

Probably 1987.

You will recall that back on February 24^th I recommended the book Genome: the autobiography of a species in 23 chapters, by Matt Ridley.  Well, I confess that there have been some mind-numbing moments subsequently, as I plod slowly onward toward the Epilogue.  Most of my problems arises from a lack of biological background, but part of it rests with Ridley: he cannot control his urge to be a little too cute, where straightforwardness would do a better job.  However, I still recommend the book, in large part because of Chromosome 17, the subtitle of which is Death.

Chapter 17 treats of cancer, its cause, and its potential cure.  It talks about oncogenes, tumor-suppressor genes, how they cooperate to allow cells to replenish themselves, and how when damaged they can result in cancer.  The star of the discussion is the gene TP53.  TP53 codes for the protein p53.  P53 induces apoptosis – it tells the cell when to die.  Together with several other genes – MYC, BCL-2 and RAS, TP53 sees to it that cell replication does not run wild.  To contract a cancer several  of these genes have to be disabled by mutation, in a single cell.  That would seem to be improbable, because mutations are random, and rare.  However, with trillions and trillions of cell divisions occurring during the human lifetime, it is not impossible.  Common medical wisdom apparently holds that the probability of contracting cancer roughly doubles with every decade of life - because of the accumulation of deleterious genetic mistakes.  (This is a sobering thought, in view of the fact that my 80^th birthday party is on the calendar.)

Chapter 17 is interesting and very useful for anyone trying to get a handle on cancer, such as myself.  However, it is also more than a little discouraging.  Ridley obviously was greatly excited by the potential these genetic revelations had for riding the world of cancer.  To quote:  ”There is now, for the first time in human history, a real prospect of a genuine cure for cancer…”  Your heart sings when you  read these words – until you remember that Ridley was writing in the 1990s.  As I said in some previous blog – you solve one problem, and find two more underlying it.  Babushka dolls again.