This enzyme consists of four heme (iron-containing organic ring) groups fixed in the structure that are involved in the oxygen conversion processes, although the definite mechanism that explains the catalase function is still unknown.10 Chen et al. used solvent-diffusion–evaporation and W/O/W double-emulsion method to encapsulate a composite of the antitumor drug cisplatin with catalase into polylactic glycolic acid nanoparticles (PLGA NPs).62 The results proved that catalase enhanced oxygen generation, which increased the therapeutic benefits of cisplatin in cancer cells. The gene discussed is CAT; the disease is cancer.