|Cancer has been considered as the most major cause of death in Japan since 1981, and cancers in the gastrointestinal tract and liver are most common in a variety of cancers in the whole body. To date many therapeutic approaches have been developed, but there have been few strategies proposed against minute cancers. Aim of our research is to decipher the mechanisms of carcinogenesis and to modulate and/or regulate functions of the key molecules. We are attempting to 1)reveal the key molecules which may account for apoptosis of cancers cells, and to develop the counter strategy for drug resistance, 2)understand the mechanism(s) of escape from immune surveillance, 3)examine the mechanism(s) of metastasis and invasion in terms of regulating key molecules, 4)reveal the relation between viral or bacterial infection and carcinogenesis. On the basis of data obtained from the projects above, we wish to develop molecular target therapy in order to prevent cell growth and metastasis of cancers in the gastrointestinal tract and liver.