In fact, GRP94 was overexpressed in a brain metastatic variant from breast cancer (435-Br1) compared to the parental cell line (435-P), while there were no differences in GRP78 expression, another chaperone involved in the UPR response (Supplementary Figure S1) and previously linked to lipid metabolism [19,25]. This evidence concerns the gene HSP90B1 and breast carcinoma.