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One of the pioneer studies of its kind, this research aimed to examine the genetic makeup of people suffering from bowel cancer in order to identify the genes that could be involved in the etiology of this deadly disease. The study identified five potential new genes whose mutation can be the cause of rare cases of bowel cancer.
This large scale study was conducted by researchers from The Institute of Cancer Research in London and was funded by Cancer Research UK. It was led by Professor Richard Houlston, Professor of Molecular and Population Genetics at The Institute of Cancer Research, London. During the course of research, around 1,000 people with bowel cancer were studied. The study was subsequently published in Nature Communications.
Genetic Causes of Bowel Cancer Unearthed
Following the study, the scientists came to the conclusion that almost all the principal genes involved in bowel cancer have been discovered. The researchers further added that these major genetic causes account for less than 1/3rd of the familial cases of colon cancer, the types of bowel cancer that tend to run in families. In nearly 12% of the cases, a positive family history of bowel cancer was found. Genes like APC and MLH1 were found to play a major role in these cases.
It was inferred that the remaining cases of bowel cancer must be caused, to a large extent, by the inconsequential variations in the DNA, which when weighed together with the environmental factors, significantly increase the risk of developing colon cancer. Lifestyle factors, especially diet, along with genetic and environmental influences, were identified as key factors in sporadic cases of bowel cancer. Understanding the roles played by these factors is essential for comprehending the full extent to which these genes can lead to bowel cancer.
DNA Sequencing Of Patients with Bowel Cancer
The researchers tried to delve further into the genetics of bowel cancer and sequenced the DNA which is involved in the production of protein, known as the “exome”, from the patients involved in the study. These patients were chosen from among 25,000 cases at The Institute of Cancer Research (ICR). All of these patients had two factors in common-early age of onset and a strong family history of bowel cancer.
This exercise helped the scientists confirm that there are no other major genes associated with bowel cancer. 12 major genes were agreed upon as the principal genetic causes of bowel cancer. This figure excluded the newly discovered genes that have been implicated in the etiology of bowel cancer. These major genes have been associated with 15-31% of the 1,000 familial cases of bowel cancer.
One of the key findings of the study is that the minor variations in the genetic makeup-nearly 30 in total-account for more cases of the bowel cancer than was previously thought. It was postulated that many more of these slight differences in the genes are yet to be unearthed. The detection of these genes can have far reaching implications in understanding the precise causative factors of the disease along with its potential new treatments and ways of prevention.