Genetic Causes of Bowel Cancer Demonstrated Clearly

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. 

Eating Oily Fish May Enhance the Survival Rate in Bowel Cancer Patients

A recent study has led to ground-breaking discovery that the consumption of oily fish in people suffering from bowel cancer can increase the likelihood of survival. This fact has been attributed to the omega 3 fatty acids which are present in rich amounts in oily fish and are responsible for inhibition of the growth of cancerous cells. 

The research was carried out by scientists from Harvard Medical School, Harvard TH Chan School of Public Health, and Massachusetts Institute of Technology and was funded by US National Institutes of Health along with some charities. The study was later published in Gut. 

This prospective cohort study involved 1,659 patients of bowel cancer and spanned a period of 10 years. The researchers examined the data obtained from 1984 and 1986 until 2012. The method of data collection that was employed included detailed questionnaires about the lifestyle, especially diet, and the health status of the patients diagnosed with bowel cancer. 
The basic aim of the study was to determine the exact amount of oily fish that could be beneficial for patients of bowel cancer. The scientists studied the consumption of whole fish as well the fish oil supplements. The possibility of dying from other cause was also explored in these individuals. The results of the study were adjusted for various confounding factors such as other causes of death, age, ethnicity, exercise and smoking. 

Consumption of Oily Fish Prolongs Survival in Bowel Cancer Patients

Of the 1,659 patients included in the study, 561 died during the course of research. Out of these patients, 169 died as a result of bowel cancer whereas others died due to cardiovascular disorders and other kinds of cancers. 

The researchers determined that the odds of death in patients of bowel cancer who ate oily fish were greatly reduced. At the same time, it was concluded that the consumption of oily fish did not reduce the likelihood of death from other causes. However, the scientists felt a dire need to conduct further research in order to confirm these results and to rule out the confounding effect of other lifestyle factors.
The researchers stipulated that patients who ate at least 0.3 grams of oily fish daily carried 41% lesser risk of dying from bowel cancer as compared to those who consumed less than 0.1 grams of oily fish on a daily basis. No variation was discovered for the risk of dying from other causes. The study effectively ascertained the role of oily fish consumption in reducing the risk of bowel-cancer related mortality.  

Recommendations 

The scientists deduced that since the number of patients included in the study was too small, further research is needed in order to establish these facts. Furthermore, this study did not establish a cause-and-effect relationship between survival after the diagnosis of bowel cancer and the consumption of oily fish. 
It was established that consuming oily fish on a regular basis can help reduce the risk of death from bowel cancer by up to 70%. The researchers recommend eating two portions of oily fish on a weekly basis in order to boost the chances of survival.