Furthermore, studies in human leukemia cells, parotoid acinar cells, and human T lymphocytes (Takuma et al., 1996; Ambach et al., 2000) report that PP1/PP2A can interact directly with cofilin, this interaction is stimulated by agents activating cofilin, and that the activation of the cofilin can be inhibited by PP1/PP2 inhibitors (Ambach et al., 2000). This evidence concerns the gene PTPA and leukemia.