What are the main causes of leukemia?

Random mutations...: occur in our body's cells because they are not able to correct all of the millions of DNA damage events that naturally occur during our life. In the event that a bone marrow progenitor cell gets hit with an unlucky series of mutations then a leukemic cell will be made, and grow out of control. Familial susceptibility, or exposures (e.g. chemotherapy, radiation, or benzene) may increase this risk.