Geography, ethnicity and "roots" in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is the most common leukemia in Western countries including Israel, and is less frequent in the Orient, Asia and Middle Eastern Arabic speaking countries. These trends persist in migrants to other countries, continuing into subsequent generations. Biological and genetic disparities have been reported for different ethnic groups. The absence of an association between place of birth and the occurrence of CLL is more in line with a genetic basis for the geographic variations in incidence. Genetic predisposition to CLL is supported by the documented familial aggregation of CLL, with an increased frequency of 8.5-fold among first-degree relatives of patients with CLL and the detection of CLL-like clones in 13.5% of first-degree relatives. It is likely that the development of CLL depends on the interplay of a genetic predisposition with exposure to environmental factors. To better understand the interplay of ethnicity and CLL we reviewed all the available literature on ethnic specific differences for this common form of leukemia.