Some types of leukemia are more likely to develop in people with other cancers who are treated with certain chemotherapy drugs. Combining those drugs with radiation therapy heightens the risk. But many people with one or more of these risk factors never develop leukemia. And most of the people who do develop the disease have no risk factors at all. The cause of most leukemia is still unknown.
Scientists do know that most leukemias are associated with specific gene mutations.
The remaining 20 percent have no symptoms. Their cancer is discovered by blood tests taken for other reasons or during a regular checkup. Specific blood tests need to be carried out to determine if leukemia is the cause of symptoms. These blood tests will show changes in your blood cells. But even if these findings indicate leukemia, an accurate diagnosis usually depends on testing a sample of your bone marrow cells.