Identification of tumour associated genes in Chronic Lymphoid leukemia (CLL) by suppression subtractive hybridization. CLL is the second most common type of leukemia in adults in the Western world. The hallmark feature of CLL are an increased frequency of circulating clonal leukemic B cells that express CD19, CD23, CD5, and have low levels of surface immunoglobulin (sIg). There is evidence that genetic components contribute to the aetiology of CLL but no definitive susceptibility genes have been identified. Genome-wide association studies have identified seven genetic variations (SNPs) associated with an increased risk of CLL, however their precise role in CLL pathogenesis is not known.