NQO1 and liver cancer: Another studied enzyme is azoreductase, which is a reductase enzyme extensively studied in the case of liver cancer, so that Medina et al. [75] reported the development of enzyme-activated nanoconjugates for the treatment of liver cancer through the release of DOX by using L1-L4 azo-linkers to conjugate a generation of 5 of poly(amidoamine) dendrimer and designed to be able to bind to hepatic azoreductase enzymes.