Leukemia is a type of cancer of the bone marrow and blood. It was first discovered in the 19th century by European physicians, who called it Weisses blut or white blood. Eventually, the disease was called leukemia, derived from the Greek words leukos meaning white and haima meaning blood.
Chronic lymphocytic leukemia, or chronic lymphoid leukemia (CLL), is one of several different types of leukemia. It is characterized by a gradual increase in the number of white blood cells, or lymphocytes, in the blood and the bone marrow. White blood cells are important because they fight bacteria and protect the body from possible infections.
The incidence of chronic lymphocytic leukemia increases with age, where 90% of cases occur in people older than 50. By 70 years of age, 15 out of 100,000 people may have it. Men are two to three times more likely than women to develop the disease.
Researchers believe that genetics plays a role in its development because it is rare in Asian countries such as Japan and China, and it remains uncommon in Japanese people who have moved to North America. This condition is more common in Caucasians, followed by people of African descent, Hispanics, and First Nations.