Nobel Laureate Dr. Harold Varmus lecture at the National Institute of Immunology to celebrate 30 years of DBT focused on grasping complexity of cancer and seeking simple solutions to deal with it.
“Most cancers are not that simple. Cancer is not one disease. It arises from hundreds of different cell types in our bodies as a result of many kinds of changes in a cell’s genome,” said Dr. Varmus during his lecture on Recent Developments in Cancer Research.
According to him, these genetic variations can affect hundreds, even thousands, of genes, making every cancer different. Cancer is also resistant to targeted drugs and the outcome of such resistance was unpredictable.
He added that cancer scientists have produced lots of data and strategies to begin dealing with the complexity of cancer. “One of the extraordinary advantages we have achieved today is that we are able to look at all the mutations that have occurred, all of the variations that were inherited, all of the RNAs that are made from that genome in the cancer cell, and even look at modifications of the DNA and proteins made from the DNA,” Dr Varmus pointed out.
In cancer research he highlighted the necessity to focus on patterns, pathogens, physiological changes, not just individual-genes, address essential host response as common to many cancer and not just genetically damage cancers cells and emphasize public health-prevention and global burden of death as well as treatment in advanced cancers.
Dr Varmus was a co-recipient (along with J. Michael Bishop) of the 1989 Nobel Prize in Physiology or Medicine for discovery of the cellular origin of retroviral oncogenes.
Tracing the history of cancer research he said, one of the early studies was the identification of Rous sarcoma virus (RSV) in 1910 by Peyton Rous which was found to trigger cancer in chickens. It was the organism in which scientists’ first detected cancer-causing genes, known as ‘oncogenes’, which could transform a healthy cell into a cancerous one that grew without stopping.
RSV is a retrovirus – its genome is in the form of RNA. This is copied into DNA, which is integrated into the infected cells’ DNA. RSV’s genome is mostly composed of genes for the virus’s multiplication, but it also carries a gene called SRC, now known as a viral oncogene, that transforms cells to cancerous ones. However, by the mid-1970s, many scientists were convinced that most human cancers were not caused by viruses and certainly not by retroviruses.
Dr Varmus explained that at present all research is geared towards finding ways to tackle cancer that work better for individuals without any side-effects of modern drugs. He added that there are several drugs like Gleevec that will allow cancer patients to a relatively normal lifespan. He said that though such drugs need to be taken throughout life, they are relatively non-toxic and quite cheap. Besides, they are effective in several cancers.
While Dr. Varmus acknowledged that complete prevention, treatment of cancer was a distant dream yet, it is possible to lower incidence and death rates from cancer by reducing the smoking, bad diet, alcohol use, inactivity, and excessive exposure to sunlight.
Other methods to prevent cancer would be to use available vaccines against cancer-causing viruses (such as hepatitis B (HPV) and papilloma viruses (HPV); and by taking precautionary measures to protect individuals who inherit the several known gene variants that confer significantly increased risks of cancer.
Dr Varmus emphasized that the most crucial step to reduce cancer suffering and deaths was detection at early stages and hence he underlined the necessity of research on early detection methods.
At the end of the session Dr. Chandrima Shaha, Director NII thanked Dr. Varmus for his valubale time and lecture.