Question: how do people get lukiemia?

Hi dif004, thanks for the question. Leukemia is ultimately caused by mutations in DNA, which mess up the blood cell’s ability to control its own growth. There are a great number of different mutations in different genes (and they occur in different combinations, too), all of which contribute to leukemia differently. But what causes the mutations? Most of the time, they are just the fault of the cells not dividing properly. When a cell divides it needs to make a copy of its DNA so that each of the two cells it divides into has a complete copy of the DNA. Usually cells are pretty good at this; they have proof-reading enzymes that check for copying errors and make corrections if necessary. Unfortunately the system isn’t perfect though, and this is where a lot of mutations come from. Mutations can also be caused by exposure to certain chemicals and radiation, but this is not a very frequent cause of leukemia. It is a more frequent cause of some other cancers; for example, smoking exposes the lungs to a number of mutation-causing chemicals and can cause lung cancer.