Dexamethasone is a synthetic glucocorticoid that is widely used in clinical due to its multiple pharmacological effects. Recently, dexamethasone is increasingly utilized in anti-cancer therapy. It is frequently used to prevent side effects of chemotherapy such as nausea, vomiting and pain, as well as to increase the anti-tumor activity of the cancer chemotherapeutic agents as a chemosensitizer and to inhibit tumor growth as an anti-cancer agent in some certain cancers. Dexamethasone produces the effects in anti-inflammation, anti-angiogenesis, control of estrogen activity and so on, by binding to glucocorticoid receptor to regulate gene expression of some important bio-signal molecules. Those signal pathways could interfere with the transcription of various factors which can regulate proliferation, invasion and metastasis of tumors.