Growth and survival of B-chronic lymphocytic leukaemia cells

Although chronic lymphocytic leukaemia of B cell type (B-CLL) is the most c ommon form of leukaemia in the Western world, several questions about the b iology of B-CLL remain to be clarified, To obtain a conceptual model for B- CLL, defined as a relentless accumulation of resting B-CLL cells, it is par ticularly relevant to ask which cell type is the normal counterpart of B-CL L; what is the site of proliferation; which signals are involved in the rec ruitment and induction of proliferation and which signals contribute to the survival of the B-CLL cells? The significance of the studies on B-CLL cell s in vitro for the interpretation of the in vivo situation may be questione d since they oversimplify the multiple and complex cellular interactions th at occur in vivo, However, the in vitro studies have been instrumental in e lucidating signals that may regulate growth, differentiation and survival o f B-CLL cells, This knowledge, herein reviewed, can be used to put forward a hypothesis on B-CLL cell regulation in vivo.