Friday, March 11, 2011
Human growth hormone and cancer
(A 32-year-old man with Laron-type dwarfism and his 17-year-old wife)
There was an interesting article by Nicholas Wade in the New York Times on February 17th. The first two paragraphs:
"People living in remote villages in Ecuador have a mutation that some biologists say may throw light on human longevity and ways to increase it.
The villagers are very small, generally less than three and a half feet tall, and have a rare condition known as Laron syndrome, or Laron-type dwarfism. They're probably the descendants of conversos, Sephardic Jews from Spain and Portugal who were forced to convert to Christianity in the 1490s but were nonetheless persecuted in the Inquisition. They are almost completely free of two age-related diseases, cancer and diabetes."
The article goes on to describe how cancer is spread by fast-reproducing cells, and how a defect in the human growth hormone receptor -- the same mutation which causes this particular form of dwarfism -- prevents the cancer cells from spreading. The hormone which promotes growth, called insulinlike growth factor, or IGF1, also contributes to diabetes, so the dwarves are free of that disease as well. Evidently a little of the hormone is helpful in preventing heart disease, but lowering the amount somewhat could still be helpful once people are full grown. A drug which does exactly this is now available, and is used mostly to prevent acromegaly.
In fact the Ecuadorean villagers don't have a longevity rate much higher than normal, because they have a higher than average rate of accidents and alcoholism. But without those two factors, it appears that they would live longer.
What the article doesn't mention is how this knowledge might be used in treating cancer patients. If it's human growth hormone, IGF1 in particular, which causes cells to reproduce rapidly, then one would think that using the drug currently used to treat acromegaly -- Somavert -- would be helpful in treating cancer.
Usually cancer is treated by both radiation and chemotherapy. Radiation basically just zaps cancerous cells. Chemotherapy kills fast-reproducing cells. Both treatments have numerous of negative side effects. Would it not make sense to lower the level of IGF1, cutting off the agent which spreads cancer at its source, with fewer side effects? (This certainly wouldn't negate the need for radiation to kill existing cancer cells.)
I wouldn't be surprised if they start using Somavert as a cancer medication.