However, in anaplastic large cell lymphomas (ALCLs), an oncogenic mutation, such as in the N-terminal portion of nucleophosmin and in the intracellular domain of anaplastic lymphoma kinase (NPM-ALK), in cells may lead to a weak expression of the p16INK4a/Rb tumor suppressive pathway. This evidence concerns the gene RB1 and anaplastic large cell lymphoma.