MCL1 and B-cell chronic lymphocytic leukemia: The role of the PI3K/AKT pathway in CLL proliferation can be attributed to a chemotactic response mediated by CXCL12 and 13 and CCL19 and 21 (69, 116) and assists in the survival of cancerous cells in response to various exterior stimuli conveyed through CD40L (117), BCR (91), CCL19 and 21, vascular cell adhesion molecule 1, and anti-apoptotic proteins, such as BCL-2 and MCL-1 (90).