Combined E2 and P4 treatment of DCIS xenografts formed by intraductal injection of ER+/PR+ DCIS.COM cells stimulated up-regulation of a NEMO/NF-κB/IL-6 pro-inflammatory pathway that relied on NEMO to maintain expression of the PML tumor suppressor. The gene discussed is PGR; the disease is ductal breast carcinoma in situ.