The invention provides a method for treating cancer comprising the step of administering a therapeutically effective amount of KPC1, a peptide which is at least about 70% homologous to the KPC1 or an agent which up-regulates KPC1. In some embodiments, there is also provided a method for treating cancer comprising the step of administering a therapeutically effective amount of p50, a peptide which is at least about 70% homologous to the p50 or an agent which up-regulates p50.