However, although preclinical studies on HO-1 and its inducers in the treatment of acute and chronic kidney diseases are abundant and have shown beneficial effects, their side effects are also evident (80): First, in recent years, more and more evidence supports that the excessive upregulation of HO-1 is related to the poor prognosis of certain malignant tumors (81), especially breast cancer, renal cell carcinoma, and liver cancer. This evidence concerns the gene HMOX1 and hereditary clear cell renal cell carcinoma.