To study the role of canonical NF-κB signaling in myeloid cells in breast cancer we crossed LysM-Cre/IkkβF/F (IkkβΔmye) mice [11] with mice that carry the polyoma middle T oncogene under the control of the MMTV promoter (MMTV PyMT) [37]. Here, NFKB1 is linked to breast cancer.