BCL-2 in B-Chronic Lymphocytic Leukemia
B-chronic lymphocytic leukemia (B-CLL) is a human B-cell malignancy characterized by the relentless accumulation of long-lived mature B cells that have two distinctive features. First, more than 99% of the circulating malignant lymphocytes are in the Go phase of the cell cycle (Andreeff et al. 1980; Carlsson et al. 1988). Second, B-CLL cells express the CDS surface molecule (Caligaris-Cappio and Janossy 1985). Crucial to our understanding of the development and natural history of the disease is to define which is the cellular origin of B-CLL and which mechanisms favour the progressive accumulation of malignant resting CD5+ B cells. The phenotype of B-CLL cells (Caligaris-Cappio and Janossy 1985, Freedman and Nadler 1990; Schena et al. 1992) suggests a similarity with mature B lymphocytes that are found in the mantle zone of secondary follicles and lends credit to the hypothesis that the normal counterpart of B-CLL may be a long-lived, recirculating subpopulation of mantle zone B cells (Galton and MacLennan 1982). As, in adult lymphoid tissues, CD5+ B lymphocytes are located within the mantle zone of secondary follicles (Kipps et al. 1991) it is not unreasonable, though still unproven, to suggest that the CD5+ B cell population might be the actual normal counterpart of B-CLL.
KeywordsChronic Lymphocytic Leukemia Secondary Follicle Mantle Zone Major Breakpoint Region Human Follicular Lymphoma
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