Chronic Lymphocytic
Chronic Lymphocytic Leukemia (CLL) results from an acquired (not inherited) injury to the DNA of a single cell, a lymphocyte, in the bone marrow. This change in the cell’s DNA confers a growth and survival advantage on the cell, which becomes abnormal and malignant (leukemic). The result of this injury is the uncontrolled growth of lymphocytic cells in the marrow leading invariably to an increase in the number of lymphocytes in the blood. The leukemic cells that accumulate in the marrow in chronic lymphocytic leukemia impede normal blood cell production, but not as profoundly as in acute leukemia.
According to the National Center for Chronic Disease Prevention and Health Promotion of the Centers for Disease Control, the incidence of Chronic Lymphocytic Leukemia (CLL) in the United States is about 4 cases per 100,000 population.
Many epidemiologic studies have been conducted of benzene-exposed workforces. While the strongest causal association found in these studies is for benzene and Acute Myelogenous Leukemia (AML), a causal association has also been found for Chronic Lymphocytic Leukemia (CLL) based upon several epidemiologic studies and case series, that together comprise a sufficient body of data to conclude that benzene causes Chronic Lymphocytic Leukemia (CLL).