The threat of cancer to human being' s health is definite.In order to find more effective cures,experts has always taking the mechanism of tumorigenesis as a research foucus and hot spot.As everyone knows,the basic biological behaviors of malignant cells have changed a lot,such as cell proliferation,apoptosis,and so on,and the causes are related to the aberrant methylation reaction occurred in these cells.Researchers have found out that DNA methylation in tumor tissues were obviously different from that in normal tissues,with the charateristics of extensive hypomethylation and localized hypermethylation.To identify the effect of abnormal methylation reaction in the evolution and progression of tumor,this article is aiming to overview those previously researches about the abnormal methylation reaction in tumor cell and its effect on cell growth.

Intrahepatic cholangiocarcinoma,which occurrence and development involved kinds of cells and genes changes,is a vital part of the primary carcinoma of liver.The cellular origin may includes bile duct epithelial cells,hepatic stem cells and hepatic cells.The macroscopic type may includes:nass-forming types,periductal infiltrating types,intraductal growth types.The fact was revealed that different macroscopic type of intrahepatic cholangiocarcinoma has different clinical features,outcomes and prognosis.The author reviewed recently published studies covering various aspects of intrahepatic cholangiocarcinoma,focusing especially on the macroscopic subtypes and related cell features,to discover the relaticn between macroscopic type and cellular origin of intrahepatic cholangiocarcinoma and better understand the pathogenesis of intrahepatic cholangiocarcinoma.