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Genetic testing vital for effective treatment of cancer

Prof O S Reddi & Dr V Ramachandra RaoThursday, December 25, 2014, 08:00 Hrs  [IST]

Recent research has provided a clear picture why the cancer drugs work only for specific tumours but ineffective against others. Dr. Levi Garraway at the Dana-Farber Cancer Research Institute in Boston, USA has carried out genetic tests on several different forms of cancer cells from many different patients before assessing the effectiveness of 24 anti-cancer drugs on them. They found that there are genetic changes. Cancer cells are derived from the host’s cells, so each individual tumour will have a genetic code. There are recurrent characteristic changes in the genes that one can see across many tumours from different individuals. It is these changes or mutations that lead testing the most effective drug.

Thus genetic testing will give the patients an opportunity to have an effective treatment. Thus patients need not be subjected to futile treatment that will lead to toxicity when their life span is in danger. Thus routine genetic testing for cancer patients has to be made so as to decide the treatment. There are several diseases where genomics (genetic testing) have an impact.

Cancer is a special case where the treatment can be made most effective with the knowledge on the genome of cancer cell. In other words cancer therapy is the first field in which genetic testing has to be done to have an effective response to treatment. Thus genetic testing of cancer cell in a patient is absolutely necessary to save life since each individual tumour will have a unique genetic code. Thus the cancer treatments rely on tailor made therapies.

Genetic basis for pancreatitis
The latest publication in “Nature genetics” journal indicates that malfunction of pancreatic gland is due to genetic causes. It is a joint research done by CCMB (Centre for Cellular and Molecular Biology) and Asian Institute of Gastroenterology. The non-function of pancreatic gland has been due to excessive alcohol consumption and malnutrition which is the scientific opinion till now.

Diabetes in humans results due to non-function of pancreatic gland that results in the circulation of sugar in high levels. Non-digestion of food leads to stomach ache. If this is ignored then it results in the cancer of pancreas.

Chronic pancreatitis results in the incidence of cancer to the extent of 10 per cent due to genetic changes as well. The present expenses to check this state of chronic pancreatitis involves to an expenditure of Rs. 5,000. Whole body genome sequence now costs about Rs.70,000 which may come down to Rs 30, 000 in the future.    Now the work has to be intensified to diagnose early and develop detection systems that take time.

Nano silver to treat Gonorrhoea
Today the situation is that antibodies developed a decade ago or so have become useless as the bacteria developed resistance. This is due to a feature called mutation in the genome of microbe.

The present situation is that many microbes have developed resistance to antibodies. The latest is gonorrhoea which has become drug resistant. During 2002, 15 per cent of gonorrhoea patients were found to be resistant to antibiotic Cefixime and by 2010 the situation accelerated to 17 per cent which has to be treated by a high dose of Ceftriaxone and Azithromycin that reduced the resistance to 11 per cent with in a year.

The latest situation is that any disease caused by bacteria or even viruses can be prevented by the administration of nano silver. Thus nano silver has become a universal killer of microbes.

Complex interaction between genes on diabetes and obesity

Research scientists at Lund University, Sweden have found that physical activity changes the action of genes involved in the storage of fat. Exercise affects the chemical groups attached to DNA (the genetic material) in a process called methylation causing genes to be switched on or off. It was found that 7000 genes are affected by the exercise and found that exercise reduces activity of key genes involved in the storage of sugar from blood stream inside fat cell.

Scientists have conducted investigations on 23 persons who are slightly over weight and otherwise healthy and none of them were engaged in regular physical activity previously. Then they were allowed to undergo exercises for six months. These people attended spinning and aerobic exercises for 18 hours in a week. DNA samples were collected from the fat cells of the volunteers before and after exercise regime and compared methyl groups in both. Changes in the methyl groups were observed.

Analysis of 4,80, 000 sites in each person’s DNA revealed that 17, 975 locations have undergone changes in 7,663 genes. The human genome has 20,000 genes. Their publication in PLOS Genetics dated June 27, 2013 claims the complex interaction between genes on diseases like diabetes and obesity. Exercise changes the way fat is stored.

 
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