We next investigated the effect of CLL B-cell differentiation in PMA/CD40L/c system on the expression of factors associated with CLL pathogenesis, including LEF1, TCL1, ROR1, FMOD, TNFRSF13B/TACI, BIRC5/survivin [55], p27, PI3K and BTK. This evidence concerns the gene BIRC5 and B-cell chronic lymphocytic leukemia.