 Hemoxygenase-1-HO-1 is a rate-limiting enzyme of heme degradation and plays an important role in the protection of cells from oxidative stress. Recent studies have shown that HO-1 is associated with chemo-resistance in various cancers, suggesting its potential use as a therapeutic target. In particular, HO-1 has been found to be involved in the regulation of apoptosis resistance, autophagy activation, and ROS detoxification, all of which contribute to chemo-resistance. Furthermore, inhibition of HO-1 has been demonstrated to reverse chemo-resistance or improve chemo-sensitivity in multiple cancers. Thus, HO-1 may serve as a novel target for overcoming chemo-resistance and improving the prognosis of cancer patients. This article was authored by Huan Wang, Qi Cheng, Ling Jiabao, and others.