Interestingly, S-adenosylmethionine decarboxylase proenzyme (AMD1) is a key enzyme involved in the synthesis of SPD, and AMD1 up-regulates the stemness of hepatocellular carcinoma cells through obesity-associated protein (FTO)-mediated mRNA demethylation; a poor prognosis is suggested when AMD1 is enriched in human HCC tissues [26]. The gene discussed is FTO; the disease is hepatocellular carcinoma.