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What Is Chronic Myeloid Leukemia?

Chronic myeloid leukemia (CML) is a rare cancer that affects blood cells and bone marrow. That’s the soft part inside the bone where blood cells are made.

Treatment may help you go into remission. For most people, that doesn't mean the cancer is completely gone, but it does mean that it’s less active than before. Remission can last for many years.

CML usually starts in middle age or later. Its symptoms tend to come on gradually. Many of them, like being tired, losing weight without trying, or having fevers, can also be signs of other illness, so learning that you have it may come as a surprise.

CML is sometimes also called chronic myelogenous leukemia.

It starts with a problem in the genes of your blood cells. Sections of two different chromosomes switch places and produce a new one.

This new chromosome starts your body making white blood cells that don’t work as they should, and too many of them. They’re called leukemia cells. This leaves less room for healthy white and red cells and platelets, the three different types of blood cells.


Most people will never know what caused them to get CNL. You don’t get it from your parents, or from infections. Your smoking habits and diet don’t seem to raise your chance of getting it either.

The only known risk is exposure to high levels of radiation.