Leukemia develops when there is an excess of abnormal WBCs in the body. This condition affects more than 45,000 people in the country every year. It is the most common blood cancer in seniors above 55 and children below 15. Knowing the common types of the condition and their symptoms can ensure one gets treatment in time. So, here are five of the most common types of leukemia.

1. Acute lymphocytic leukemia (ALL)
This condition progresses fast. It replaces the healthy cells producing functional lymphocytes with mutated ones, which cannot grow properly. These unhealthy cells are then carried onto the bloodstream and transported to various tissues and organs, such as the brain, lymph nodes, and liver, where they continue growing and dividing.

2. Acute myeloid leukemia (AML)
Also called acute myelogenous leukemia, this condition is a quick-growing form of cancer in the bone marrow and blood. It is most commonly found in grownups, and it progresses very fast. It can affect many blood components and has several sub-types.

In AML, the myeloid stem cells mature into abnormal myeloblasts or WBCs, sometimes even into abnormal RBCs and platelets. Once they multiply, they can outnumber the normal cells inside the blood and bone marrow and spread to different body parts.

3. Chronic lymphocytic leukemia (CLL)
This is relatively slow-progressing leukemia and starts in the lymphocytes inside the bone marrow. These extend to the blood and may spread even to organs like the spleen, liver, and lymph nodes. CLL occurs when excess abnormal lymphocytes grow and crowd out the healthy blood cells.

4. Chronic myeloid leukemia (CML)
This form of leukemia starts in the bone marrow and eventually spreads to the blood and other body parts. Grownups are more likely to get this than kids. CML will occur when genetic changes transform myeloid cells into abnormal and immature cancerous cells. Such cells grow slowly but overwhelm healthy cells inside the blood and bone marrow.

5. Hairy cell leukemia (HCL)
This is a chronic lymphocytic leukemia that is rare and progresses slowly. The condition develops when the bone marrow produces excess B cells or lymphocytes meant for fighting infection. When leukemia cells increase, there are fewer healthy RBC, WBC, and platelets around.

All common types of leukemia will develop whenever the bone marrow WBC starts to experience mutations called leukemic changes. These changes accelerate the process of growth and cell division for replacing the old or damaged cells. In time, the accumulation of these mutated cells starts to outnumber the healthy WBCs, RBCs, and platelets, resulting in leukemia.