 Anaplastic large-cell lymphomas (ALCL) are frequently associated with the chromosomal translocation t(2;5) (p23;q35) resulting in the NPM/ALK fusion gene that encodes a constitutively activated tyrosine kinase.     ///    NPM/ALK downregulates p27Kip1 in a PI-3K-dependent manner..     ///    In this study we investigated the role of PI-3K/AKT in NPM/ALK-dependent downregulation of p27Kip1 protein.     ///    "p27Kip1 was found to be downregulated in NPM/ALK-transformed hematopoietic cells, but inhibition of proteasome-dependent degradation pathway by epoxomicin reversed this effect. "    ///    "Taken together, we postulate that NPM/ALK-PI-3K pathway stimulates cell proliferation by regulation of the expression and nuclear localization of p27Kip1.. "    ///    "To investigate this phenomenon the pro-B cell line BaF3, BaF3 cell line stably expressing NPM/ALK, and ALCL SUP-M2 cell line were used. "    ///    We showed that NPM/ALK stimulated cell proliferation and that PI-3K/AKT pathway played an important role in this effect. 