In ALK+ALCL, NPM-ALK affects the activation of Rac1 and Cdc42 and the re-localization of Cdc42 (86, 96) culminating in the phosphorylation and activation of p21-activated kinases PAK2 and on morphologically large cells with a polarized distribution of F-actin (86). Here, CDC42 is linked to anaplastic large cell lymphoma.