RETREG1 and cancer: In addition, we further observed that the entirely unrelated and non HDAC-inhibitory anti-diarrheal drug Loperamide, as well as the anti-viral compound Nelfinavir, could also induce the ER-phagy receptor FAM134B. This underscores the importance of the ‘FAM134B→ ER-phagy→ ER-stress→ apoptosis’ axis in the treatment of cancer, also with clinically approved drugs.