Scientists Shed New Light On Bowel Cancer Genetic Link

Main Category: GastroIntestinal / Gastroenterology
Also Included In: Cancer / Oncology;  Genetics
Article Date: 24 Apr 2009 - 0:00 PDT

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European scientists have found a genetic variant which they believe can promote the development of bowel cancer, the second most common cause of cancer death in the UK. The finding, which is being published online tomorrow (April 24, 2009) in the journal Genome Research, sheds new light on how this disease develops and could lead to new treatments being designed.

The study has been led by scientists at The Institute of Cancer Research (ICR) in London and partly funded by Cancer Research UK. The ICR scientists had previously found common genetic variants associated with bowel cancer, but have gone one step further by showing how a precise DNA sequence could cause biological changes that ultimately lead to cancer.

Lead author Dr Alan Pittman says: "Scientists had already found many genetic variants that give people a higher risk of bowel cancer, but we didn't know how they might be driving cancer development. This is the first time we've provided evidence of how a common genetic variant may promote bowel cancer. Understanding cancer development in such detail will help in the search for new drugs, as any steps identified in the cancer process are potential places to intervene with treatments.

The ICR scientists sequenced the DNA of bowel cancer patients, comparing them with healthy controls and looking for differences between them.

They honed in on the genetic variant that conferred the strongest risk of bowel cancer, hypothesising that it was therefore key to driving cancer development.

Laboratory experiments supported the scientists' theory, showing the key genetic variant stopped the nearby SMAD7 gene turning on properly. It was already known that disrupting the SMAD7 gene promoted cancer development.The SMAD7 gene is normally involved in cell growth and death so, by reducing the gene's effect, the variant allows cancerous cells to grow.

Although the extra risk from having this DNA is modest, Dr Pittman says the finding is significant because a large proportion of the population have the variant as part of the genetic makeup.

Professor Richard Houlston, who oversaw the research as head of the ICR's Molecular and Population Genetics Team, says: "Unravelling how a genetic variant promotes cancer development is an important step forward, and the key to ultimately working out the causes of cancers."

Scientists in the UK, Spain and The Netherlands contributed to the study, which was funded by Cancer Research UK, the European Union, the Spanish Ministry of Education and Science, Junta de Andalucía, the Dutch Cancer Society and the ICR.

Source
Institute of Cancer Research

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