MTOR and cancer: Mutations of PIK3CA are activating, while those of PIK3R are inactivating, and both result in enhanced PI3K activity, with downstream activation of Akt and mammalian target of rapamycin, which are associated with aggressive clinical behavior in many cancers.30 Our neural network identified INPP4B, a known suppressor of PI3K signaling,31 as a protein whose increased expression was strongly associated with improved outcome.