Notch signal pathway has extensive influence on the growth and development of cells through modulating cell differentiation,proliferation and apoptosis.It also interacts with the key pathways of tumor formation and progression.Its relationship with tumor is initially established through T cell leukemia induced by mismatch or chromosome translocation.Increasing evidence showed that Notch pathway is associated with the formation and progression of the other types of tumor,such as skin cancer,liver cancer,brain tumors and breast cancers.Notch signal pathway has promoting effect on some tumors (such as brain tumors and breast cancer) and inhibitory effect on others (such as skin cancer and liver cancer).Close relationship was found between Notch pathway and tumor stem cells.Moreover,it may have different functions for different subtypes and different stages of one tumor.