hronic lymphocytic leukemia (CLL) is a clonal lymphoid neoplasm characterized by proliferation and accumulation of neoplastic B lymphocytes in the blood, bone marrow, lymph nodes, and/or spleen. In Western countries, CLL is the most common leukemia in adults, accounting for 5% to 11% of lymphoproliferative disorders (LPD). The incidence rate is between 2 to 6 cases per 100 000 with an increasing trend as people get older.1 The incidence of CLL is lower in Asian subjects, including Malaysians. In Asian countries, CLL accounts for only 1% to 3% of LPD in most series.2 Asian CLL has been reported to have different biological characteristics with a more aggressive clinical course and treatment outcomes when compared with those of Western CLL. The reasons for these differences in incidences and clinical behaviour between geographic regions are unclear but are of considerable interest. Data on CLL in Asian countries including Malaysia is also very limited because of the disease rarity.