RAC1 and neuroblastoma: The publicly available Kocak database, comprised of 649 human neuroblastoma samples, was accessed to evaluate for associations between expression of P-Rex1 and the three Rac effectors: Rac1, Rac2, and Rac3. Rac1 is ubiquitously expressed in mammalian tissue and the most extensively studied Rac effector (30).