HSP90B1 and inflammatory breast carcinoma: The rationale for selecting to study UPR has based on 1) our findings in the previous study, where we identified that OPG binds to cellular chaperones including mortalin, chaperonin, BiP protein, HSP90AB1 protein, and heat shock protein gp96 in IBC cells (12) and 2) significantly high expression of ER stress proteins and UPR sensors in IBC cell lines and IBC tumors as compared to their healthy counterparts (Figures 1–3).