The intermediate β-selection phenotype of Itpkb-loss between those of Pten-loss (Hagenbeek et al., 2004; Kelly et al., 2007; Shiroki et al., 2007; Wong et al., 2012) and Inpp5d/SHIP1-loss (Kashiwada et al., 2006) raises the possibility that IP3 3-kinases could have tumor suppressor functions by limiting Akt signaling. The gene discussed is PTEN; the disease is neoplasm.