Another important aspect of the theory of the underlying cause of the anti-cancer effect of CAP, as presented in refs. [37,55,56,57,58,59,60], is the hypothesis that the non-decomposed hydrogen peroxide and peroxynitrite in the vicinity of inactivated catalase, may generate a burst of so-called “secondary” singlet oxygen, which is propagated to adjacent cancer cells. Here, CAT is linked to cancer.