London, Jul 29 (IANS): Researchers have discovered that mutation in a gene can led to a form of hereditary colon cancer which was not identified earlier.

The researchers discovered genetic changes in the MSH3 gene in patients and identified a new form of colon cancer.

"The knowledge about molecular mechanisms which lead to cancer is also a precondition for the development of new targeted drugs," said Stefan Aretz from University of Bonn Hospital in Germany.

The formation of large numbers of polyps in the colon has a high probability of developing into colon cancer, if left untreated.

Colon polyps form like mushroom-shaped growths from the mucosa and are several millimeters to several centimetres in size.

They are benign and generally do not cause any symptoms - however, they can turn into malignant tumours (colon cancer).

Physicians refer to the development of a large number of polyps in the colon as "polyposis." Scientists have already discovered several genes associated with a polyposis.

"However, about one-third of families affected by the disease do not have any abnormalities in these genes," Aretz said.

Therefore, there would have to be even more genes involved in the formation of polyps in the colon.

Together with pathologists from the University Hospital Bonn, scientists from the Yale University School of Medicine in New Haven (USA), and the Frankfurt University Hospital,

The team of US and German researchers working with Aretz investigated the genetic material (DNA) of more than 100 polyposis patients using blood samples.

In each patient, all of the about 20,000 protein-coding genes known were simultaneously examined.

In this process, the scientists filtered the rare, possibly relevant genetic changes out of the gigantic quantity of data, like the proverbial needle in a haystack.

In two patients, genetic changes (mutations) were discovered in the MSH3 gene on chromosome five, showed the findings published in the American Journal of Human Genetics.

The researchers believe that by investigating the MSH3 gene, a clear diagnosis can be made prospectively in some other, previously unexplained polyposis cases. Afterwards, healthy persons at risk in the family can be tested for the mutations.