Among 33 differentially protein spots, key mediators in the unfolded protein response (UPR) pathway, including 78 kDa glucose-related protein (GRP78), endoplasmin (GRP94), calreticulin (ERp60), and prelamin-A/C, are upregulated in osteosarcoma tissues. The gene discussed is HSP90B1; the disease is osteosarcoma.