How Down syndrome works against cancer

Science News ^ | May 20th, 2009 | Nathan Seppa

[neverdem]

Extra dose of protein limits blood vessel formation that tumors need

Surplus production of a cancer-suppressing protein may explain in part why people with Down syndrome seldom get cancer, a study in the May 21 Nature shows.

People born with Down syndrome have an extra copy of chromosome 21, instead of the usual two copies — one from each parent. The third chromosome causes genetic aberrations that result in the mental retardation and telltale physical traits that define the condition.

But chromosome 21 carries 231 genes, including some that may well suppress cancer. In the new study, researchers provide evidence that the protein encoded by the RCAN1 gene reins in the rampant blood vessel growth that a tumor needs to thrive. Scientists theorized that having an extra copy of the gene would result in more protein being made and add to an anticancer effect.

Scientists have long suspected that such genetic benefits might accrue from having an extra chromosome 21. A recent study found that people with Down syndrome are only about one-tenth as likely to get a solid-tumor cancer as are people without the syndrome.

A tumor needs veins and arteries to nourish its rapid growth. So tumors fashion a haphazard cluster of new vessels that mimic a legitimate body process called angiogenesis. The late Judah Folkman of Harvard Medical School in Boston saw angiogenesis as the Achilles’ heel of tumors and suspected that cancer suppression in people with Down syndrome could stem from extra copies of propitious genes on chromosome 21 that thwart angiogenesis.

In the new study, Folkman’s colleagues tested the antitumor effect of RCAN1, alsocalled DSCR1. The researchers compared two sets of mice, some with a third copy of the RCAN1 gene and some with the usual pair. When the mice were surgically implanted with melanoma...

[neverdem]

Down's syndrome suppression of tumour growth and the role of the calcineurin inhibitor DSCR1

Regulator of Calcineurin (RCAN1-1L) Is Deficient in Huntington Disease and Protective against Mutant Huntingtin Toxicity in Vitro

[TChad]

A recent study found that people with Down syndrome are only about one-tenth as likely to get a solid-tumor cancer as are people without the syndrome.

Fascinating. Thanks for posting this.

[LukeL]

This is what evolutions call a positive mutation, much like how those who have sickle cell anemia can’t get malaria.

[D-fendr]

Or dogs that humans breed to win shows that have deformed joints and breathing problems.

[garandgal]

Would it be too obvious to assume that the mutation is a protective reaction to something in the Mother's system that could perhaps cause cancer?

Like a virus, fungus, etc., etc.

One would think that upon noticing a lack of cancer development amongst Down's children, that would be the FIRST thing studied. Have they done that?

[Talisker]

This is what evolutions call a positive mutation...

What do non-evolutionists call it?

[Born Conservative]

A recent study found that people with Down syndrome are only about one-tenth as likely to get a solid-tumor cancer as are people without the syndrome.

Although children with Down's Syndrome are predisposed to Leukemia (which obviously is not a solid-tumor cancer).

[SunkenCiv]

Surplus production of a cancer-suppressing protein may explain in part why people with Down syndrome seldom get cancer... People born with Down syndrome have an extra copy of chromosome 21... chromosome 21 carries 231 genes, including some that may well suppress cancer.

Thanks neverdem.

[LadyDoc]

actually, Down’s syndrome is associated with an increased risk of leukemia.

And since they don’t live to old age, the low cancer rate might not be entirely true.