In the laboratory, scientists explore possible causes of cancer and try to determine exactly what happens in cells when they become cancerous. Researchers also study patterns of cancer in the population to look for risk factors, conditions that increase the chance that cancer might occur.
They also look for protective factors, things that decrease the risk.
Even though doctors can seldom explain why one person gets cancer and another does not, it is clear that cancer is not caused by an injury, such as a bump or bruise. And although being infected with certain viruses may increase the risk of some types of cancer, cancer is not contagious; no one can "catch" cancer from another person.
Cancer develops over time. It is a result of a complex mix of factors related to lifestyle, heredity, and environment. A number of factors that increase a person's chance of developing cancer have been identified:
Some people are more sensitive than others to factors that can cause cancer. Although risk factors increase the likelihood of getting a certain cancer, it is important to remember that some people who get cancer have none of the known risk factors and some people who do have risk factors do not develop the cancer.
Some cancer risk factors can be avoided. Others, such as inherited factors, are unavoidable, but it may be helpful to be aware of them. People can help protect themselves by avoiding known risk factors whenever possible. They can also talk with their doctor about regular checkups and about whether cancer screening tests could be of benefit.
Here are some additional links to get you started:
The more we can learn about what causes cancer, the more likely we are to find ways to prevent it.