Four metabolic enzymes involved in the methylation cycle in the liver were down-regulated in HCC tissues, indicating S-adenosylmethionine deficiency in HCC.

• 在HCC组织中，与肝脏中的甲基化周期有关的四种代谢酶被下调，表明HCC中缺乏S-腺苷甲硫氨酸。