Leukemia is a type of blood cancer which is caused by the infection in Bone Marrow. Through the infection in Bone Marrow, the cancer cells can directly influence the production of new cells, mainly the white blood cells/ lymphocytes which increases the chance of being caught by Leukaemia.
Leukemia is often diagnosed in kids of age under 15 years or in adults of age 45 and above. Out of all blood cancer cases, about 80-90% of them are of this category. Also, note that Leukaemia is not a one-time infection, it is developed over the period. In a healthy body, the cells grow, multiply their number and then die which is immediately replaced by other new cells whereas the infected/ cancerous cells developed in bone marrow, grow and multiplex just like healthy cells but their lifespan is increased. And if it is not detected in time, cancer cells will outrank the healthy cells in the human body and make you infected.