New perspectives on recurrence and metastasis of liver cancer.

Cancer metastasis is considered as a complex process involving a series of sequential steps and a variety of molecalar signal transduction pathways.Tumor recurrence and metastasis are major obstacles for long-term survival of Liver cancer patients.Although the prognosis after recurrence and metastasis is dismal,the advancement of molecular researches of metastasis of liver cancer seems promising.In studies of origins of metastasis of liver cancer,the primary cancer cell and corresponding metastatic liver cancer cells share similar gene signature,which indicates that genes favoring metastasis progression are initiated in the primary tumors.The metastasis of liver cancer may be an early event in hepatic carcinogenesis and progression.Some molecular signatures have been developed to classify the metastatic potential of liver cancer.Furthermore,a variety of studies demonstrate that the tumor microenvironment instead of tumor cells plays a more important role in liver cancer metastasis.The pre-metastatic niche composed of non-tumoral cells may promote the cancer cell sedimentation and progression.The theory of cancer stem cell speculates that cancer stem cells were the real source of recurrent or metastatic tumors.Cancer stem cells will be one of the main targets of liver cancer treatment.The prevention and treatment of liver cancer recurrence or metastasis are quite difficult because liver cancer is resistant to traditional chemotherapy.Targeting the molecules involved in the metastasis of liver cancer WOuld be promising to cure those diseases. Key words: Liver neoplasms; Recurrence; Metastasis