IL2 and breast cancer: There was no significant impact on time to engraftment of neutrophils or platelets using either mobilization regimen. The addition of IL-2 to mobilization increased the cytotoxicity of IL-2-activated mononuclear cells from the PBPC product against the BC cell target, MCF-7, and increased the percentage of NK cells and activated T cells in the PBPC product. The enhanced NK-cell number was sustained in the early posttransplant period