HSPA5 and breast cancer: To further investigate the impact of GRP78 S‐sulfhydration at the Cys420 residue on the metastasis of BC in vivo, WT or Mut‐Cys420 THP‐1 cells and MDA‐MB‐231 were intravenously injected into NODSCID mice, before treatment with either NaHS or PBS saline solution, as shown in Figure6A.