Since nuclear factor-kappaB (NF-kappaB) is frequently activated in acute myeloid leukemia, we questioned whether active NF-kappaB can affect the cellular properties of cord blood CD34+ cells. The results demonstrated that NF-kappaB activation did not influence growth or differentiation properties of these cells. Furthermore, NF-kappaB activation was not sufficient to induce changes in stem- and progenitor cell numbers.