Cancer Risks and Protective Factors The more we can learn about
what causes cancer, the more likely we are to find ways to
prevent it. 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 ha