Angelina Jolie chose to undergo mastectomy rather than wait to get breast cancer, because it was in her genes. Her doctors told her she was carrying the BRCA1 cancer gene, which gave her an 87% chance of developing breast cancer, and 50% risk of getting ovarian cancer. She chose to undergo preventive mastectomy for both breasts to reduce the risk, sparking off many debates about her decision.
Was she being too cautious? Do genes play such a significant role in cancer risk? To find an answer to that, we first need to understand how our genes are involved in triggering cancer.
The cells of our body contain DNA, which controls the development and normal functioning of the whole body. DNA is made up of smaller units or chemicals called bases names A, T, C and G. These bases are repeated over and over again in pairs with a particular sequence. Specific portions of these DNA strands form distinct genes, which regulate the way each cell functions and behaves.
Given that cancer is a condition in which the normal body cells start behaving abnormally, scientists always suspected that this may have something to do with the units of those cells - the genes. Research has shown that this abnormal behaviour can be attributed to changes (called “Mutations”) taking place in certain genes. Mutations occur when one of the base pairs in the gene’s DNA sequence gets switched, goes missing or is repeated additionally. These faulty genes then give rise to abnormal cell behaviour resulting in the formation of cancerous tissue.
So am I at Risk?
It is possible that an abnormal gene is the cause for the cancers in your family and you also may be at increased risk. You may want to speak to a doctor, if any of the following is applicable to you:
- Cancer in close relatives (parents, sibling)
- Same type of cancer in relatives
- Presence of a rare type of cancer
- Cancer occurring at younger age in relatives
- More than one type of cancer
Though genes play a role in their development, cancers are not necessarily always due to genes that you get from your parents. Contrary to the general belief, only about 5% to 10% of all cancers are inherited. By inherited we mean that the mutated cancer-causing gene is being passed on from parents to their children, due to which they have a high-risk of developing cancer later in life. In fact, it will be safer to say that the direct environment plays a bigger role in cancer than inherited genes do. In most cancers, spontaneous mutations occur in genes during the individual’s lifetime. These mutations are not inherited, they occur due to an interaction of the genes with harmful cancer-causing environmental agents. Environmental exposure like UV radiation, tobacco smoke, excessive alcohol consumption, certain infections, lack of exercise and unhealthy lifestyle are some factors which can cause new mutations in genes and result in cancer.
The good news here is that all these environmental factors are modifiable. That means, merely by adopting a healthy lifestyle and avoiding environmental exposure to cancer-causing agents, you can in-fact reduce your risk for developing cancer. Even if you feel you are at risk, rapid advancements in medical technology, has made it possible to ascertain the risk factor due to the inherited genes for cancer, by fairly accurate genetic testing. Researches in genetic testing have shown that mutations in the BRCA1 gene can up the risk of developing breast and ovarian cancer in women by a great extent. Then one has the option of pre-empting it, which is what Angeline Jolie chose to do.
So today anyone can have a series of medical tests done to detect mutations in cancer-causing genes. This process of genetic testing usually helps in evaluating the risk for developing a certain disease, in this case, cancer. This is the kind of observation that helps give you the power of choice. If you have observed a particular pattern in the development of cancer in your close family relatives, noticed the presence of common cancer-risk factors, or feel concerned about developing the same, it is time you visit your family doctor.
Your family doctor will be the best person to guide you, discuss the need for a predictive genetic testing and if the need be, will also refer you to the specialist for the same.