Figure 1.

The main drivers of chronic lymphocytic leukemia (CLL). The engagement of B-cell receptor (BCR) on CLL cells with an antigen provides pro-survival and proliferation signals that are transduced to the nucleus by various proteins including spleen tyrosine kinase (SYK) and/or 70-kDa zeta-associated protein (ZAP-70). C-X-C chemokine receptor type 4 (CXCR4) on CLL cells binds with its ligand C-X-C motif chemokine 12 (CXCL12; also known as stromal cell-derived factor 1) causing the malignant cells to migrate to bone marrow and close proximity to nurse-like cells (NLC). CD31 on the surface of NLC also interacts with the CD38 on CLL cells, resulting in the proliferation of CLL cells. The engagement of CD40 on CLL cells with CD40L on T-cells promotes the growth and survival of the cancerous cells.