Chronic Lymphocytic Leukemia (CLL)/Small Lymphocytic Lymphoma (SLL) - all the aspects

B-chronic lymphocytic leukemia (B-CLL)/Small lymphocytic lymphoma (SLL) is a neoplastic, lymphoproliferative disease, characterized by accumulation of small, mature lymphocytes of the Bcell line in the blood, bone marrow and lymphoid tissues. CLL and SLL are different manifestations of the same disease. The major difference is that in CLL a significant number of the abnormal lymphocytes are also found in the bone marrow and blood, while in SLL the abnormal lymphocytes are predominantly found in the lymph nodes and bone marrow. B-CLL is the commonest leukaemia in adults in the Western countries. The mean age of occurrence is in the range of 64-70 years. Adequate immunophenotyping of peripheral blood is essential for establishing the diagnosis of CLL/SLL. The typical immunophenotype for CLL/SLL is CD5+, CD10-, CD19+, and CD20 dim, surface immunoglobulin dim, CD23+, CD43 +/-, and cyclin D1-. The clinical course of the disease is highly variable. Approximately 2-10% of patients with CLL/SLL will develop histologic transformation to diffuse large B-cell lymphoma or Hodgkin lymphoma. This transformation is called Richter's syndrome and involves a much more aggressive disease and a fatal outcome. During the past decade, numerous prognostic factors were identified and include serum markers such as thymidine kinase and beta-2 microglobulin, genetic markers including IGHV mutational status and cytogenetic abnormalities detected by FISH (e.g., del(13q), del(11q), del(17p), CD38 expression, CD49d and ZAP-70 expression/methylation). During the last few years, recurrent mutations in NOTCH1, SF3B1 and BIRC3 genes with prognostic implications in CLL were also identified. Minimal residual disease (MRD) negativity determined in the peripheral blood after the end of treatment is emerging as an important predictor of treatment efficacy. Ongoing preclinical and clinical studies will unravel newer therapeutic targets and keep on improving patient outcomes and the quality of life.