CAT and neoplasm: Moreover, to establish oxygen as an alternative method for enhancing cancer treatment, there are further issues that urgently need to be explored, such as focusing on all the factors that lead to hypoxia in normal cells, converting them to tumor cells, studying if the hypoxia in tumor cells is reversible or irreversible, understanding the mechanism of oxygen inside the tumor cells and the catalase function for decomposing the H2O2 into water and oxygen, and optimizing the conditions for enhancing cancer treatment using oxygen.