It was remarkable that inhibition of p110δ in B-CLL cells or treatment of patients with the p110δ-selective inhibitor CAL-101 prevented B-CLL survival and moreover disrupted the signals from supporting cells of B-CLL microenvironment thus providing an anti-tumor activity (Herman et al., 2010; Hoellenriegel et al., 2011; Castillo et al., 2012). The gene discussed is PIK3CD; the disease is B-cell chronic lymphocytic leukemia.