Despite the popular misconception, sharks do get cancer. Though anecdotal evidence suggests that they may get cancer much less frequently than humans do, there hasn't ever been a large-scale systematic study, so it's hard to say for sure. If it is true though, then researchers may be able to figure out ways to reduce the incidence of cancer in humans by studying why it is low in sharks.
More about sharks and cancer:
- One reason sharks may get cancer less than humans is because of the way their immune systems work. Humans produce most of their immune cells in their bones, which leaves a short lag time between production and the time the cells are providing immunity. Sharks produce their immune cells in other tissues, which may give them a faster immune response.
- Like humans, sharks seem to get cancer in response to environmental toxins, including asbestos. They also get other diseases, including bacterial infections and parasites.
- Many sharks are endangered, with an estimated 100 million being killed each year.