How Down syndrome works against cancer

No politics here just a dam^ed interesting story...

Text Size 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.