Abstract: STAT3 can be activated by various cytokines and participate in the process of tumor cells proliferation, angiogenesis, invasion and chemotherapy resistance. Epithelial-mesenchymal transition (EMT) also plays an important role in the process of tumor invasion and metastasis and chemotherapy resistance. Studies have shown that STAT3 can regulate the process of EMT so as to change the invasion and metastasis abilities of tumor cells, and to enhance their ability of  chemotherapy resistance. Discussion of the role and relation of STAT3 and EMT in tumor cells will be helpful to provide reliable theory for tumor molecular targeted therapy.

Key words: Transcription factors, Neoplasms, Neoplasm metastasis, Neoplasm invasiveness