TNFRSF11B and neoplasm: To understand whether IBC cells are addicted to OPG (12) and use OPG as a critical survival factor by interacting with master ER stress regulator GRP78/BiP (41), we performed IHC, real-time qPCR, Western blotting, and immunofluorescence assay (IFA) to compare the expression of ER stress proteins in healthy human breast tissue as compared to IBC tumor tissue obtained from patients (Figures 1–3).