HMOX1 and renal carcinoma: iii) In renal carcinoma, one study found that the natural product chitosan oligosaccharide (COS) can inhibit human renal carcinoma cell proliferation in vitro and in vivo by promoting the expressions of Nrf2 and Nrf2 target genes such as HO-1, the modifier subunit of glutamate cysteine ligase, solute carrier family 7 member 11, glucose-regulated protein 78, protein RNA-like endoplasmic reticulum kinase, and cytochrome C. (Zhai et al., 2019).