HSPA5 and breast carcinoma: Subsequently, an important work from our group showed that USP22 is indeed indispensable for the biology of HER2-driven mammary carcinoma in vitro and in vivo via deubiquitinating the heat shock protein 5 (HSPA5) chaperone, ultimately suppressing the pro-apoptotic axis of the unfolded protein response (UPR) [16].