Virginia Commonwealth University

VCU Massey Cancer Center

What is leukemia?

Leukemia is cancer of the blood cells — usually the white blood cells. Leukemic cells look different than normal cells and do not function properly.

What are the different types of leukemia?

There are four main types of leukemias, which can be further divided into subtypes. When classifying the type of leukemia, the first steps are to determine if the cancer is:

  • Lymphocytic or myelogenous leukemia – cancer can occur in either the lymphoid or myeloid white blood cells.
    • When the cancer develops in the lymphocytes (lymphoid cells), it is called lymphocytic leukemia.
    • When the cancer develops in the granulocytes or monocytes (myeloid cells), it is called myelogenous leukemia. 
    • Leukemia is either acute or chronic. 
    • Acute leukemia – the new or immature cells, called blasts, remain very immature and cannot perform their functions. The blasts increase in number rapidly, and the disease progresses quickly. 
    • Chronic leukemia – there are some blast cells present, but they are more mature and are able to perform some of their functions. The cells grow more slowly, and the number increases less quickly, so the disease progresses gradually.

Based on these findings, the leukemia is then classified into one of the four main types of leukemias:

  • Acute myelogenous leukemia (AML)
  • Chronic myelogenous leukemia (CML)
  • Acute lymphocytic leukemia (ALL) 
  • Chronic lymphocytic leukemia (CLL)

There are other types and subtypes of leukemias.