Blood cancer is a type of cancer that affects the blood cells, bone marrow, or lymphatic system. Blood cancers occur when something goes wrong with the development of blood cells, causing them to behave abnormally. The exact cause of blood cancer is not fully understood, but it is believed to develop from a combination of genetic and environmental factors. Some of the risk factors that may increase the likelihood of developing blood cancer include:

• Previous cancer treatment: People who have had certain types of chemotherapy and radiation therapy for other cancers have an increased risk of developing certain types of leukemia.
• Genetic disorders: Genetic abnormalities seem to play a role in the development of leukemia.
• Exposure to certain chemicals: Exposure to certain chemicals, such as benzene, which is found in gasoline and is used by the chemical industry, is linked to an increased risk of some kinds of leukemia.
• Smoking: Smoking cigarettes increases the risk of developing some types of leukemia.

In general, leukemia is thought to occur when some blood cells acquire changes (mutations) in their genetic material or DNA, which tell the blood cells to continue growing and dividing. Blood cancers can be classified into three main types: leukemia, lymphoma, and myeloma.