In addition to classical cytokines, stromal cells secrete hedgehog ligands, which promote survival in CLL cells, as well as a range of anti-apoptotic membrane proteins such as B-cell-activating factor of the tumor necrosis factor family (BAFF), the proliferation-inducing ligand APRIL [12], and CD31 [13]. The gene discussed is TNFSF13B; the disease is B-cell chronic lymphocytic leukemia.