Extracellular membrane vesicles (EVs) are emerging as nano/microbiological devices that regulate the intercellular communication in tissues and organs under healthy and pathological conditions notably in cancer. This novel field gained a worldwide interest since the discovery that biological information (e.g., proteins, lipid, and nucleic acids) carried by EVs, and shared by donor and target cells, can transform the activity of the latter. In cancer, the secretion of EVs are often dysregulated which could promote tumor growth and lead to metastasis formation. Here, we will highlight the recent literature about cancer cell-derived EVs and their content, including the cellular trafficking of their cargo upon endocytosis as well as their relevance as diagnostic and prognostic biomarkers in cancer. The use of artificially modified EVs as vehicles for therapeutic purposes in targeting cancer cells will also be discussed.