Cancer-derived exosomes were shown to contribute to tumor angiogenesis, to transport growth promoting proteins, such as mutant KRAS, epidermal growth factor receptor (EGFR), and SRC family kinases, to induce therapy resistance by removal of chemotherapeutic drugs, and to prepare metastatic niches for the colonization of circulating cancer cells (reviewed in Miller and Grunewald 2015). This evidence concerns the gene KRAS and cancer.