By Maia Poon
According to the American Cancer Society, “Almost everyone knows someone who has had cancer.” The risk of having cancer is a serious concern for many people, especially those whose family has a history of the disease. Learning about genetics in biology has sparked my interest in multifactorial disorders, which include cancer. A multifactorial disease is “associated with the effects of multiple genes (polygenic) in combination with lifestyle and environmental factors” (Genetics Home Reference).
In this article, I will identify the factors behind cancer. Many watch their diet and physical activity as preventative measures against the disease. However, by looking at the factors, we can see that unfortunately, cancer is very much beyond our control.
How are factors found?
Many cancer risk and protective factors are initially discovered through epidemiology studies. Epidemiology is “the study of diseases in populations of humans or other animals, specifically how, when and where they occur” (Cornell University). Scientists study large groups of people, comparing those who develop the disease with those who don’t. This leads to identifying the behaviours that the people who develop cancer are more or less likely to have, or the substances they are more likely to be exposed to.
Overall, age is the most important factor for many cancer types. The median age for a cancer diagnosis is 66 years. That said, there are types of cancer which affect different age cohorts. For example, more than a quarter of people with bone cancer are under the age of 20.
Obesity increases the risk of having several types of cancer, including breast cancer, colon cancer, and cancers of various other organs. Although it can be mitigated with a healthy diet and enough exercise, obesity has been shown to be a genetic disorder.
Infectious agents, which include bacteria, viruses and parasites, can directly cause cancer or increase the likelihood of cancer forming. Many infections weaken the immune system, making the body more prone to other cancer-causing infections. In addition, chronic inflammation can occur as a result of infectious agents, which may lead to cancer.
Immunosuppression is a result of medications taken by organ transplant recipients to suppress the immune system. These drugs, which are needed so the body does not reject the transplanted organ, weaken the immune system’s defences against cancer-causing infections. They also reduce the ability for the body to detect and destroy cancer cells. Furthermore, people with HIV/AIDS have weakened immune systems, making them more at risk of cancer.
Oftentimes, people with a disease, as well as their families, will feel guilt or regret. They may find themselves asking, What could I have done differently? Who is at fault? Talking to a genetic counsellor made me realize that this feeling of guilt is especially prominent when a disease has a genetic factor.
I am interested in studying multifactorial disorders in the future because of the various fields the topic combines, including genetics and health. By determining the factors which affect the likelihood of having a disease, we can work towards developing preventative methods and finding a cure. Furthermore, we can help patients and their families deal with the strong emotions a disease often brings.