Melanoma exosomes educate bone marrow progenitor cells toward a pro-metastatic phenotype through MET

Exosomes can transfer proteins and nucleic acids from one cell to another, altering the phenotype of the recipient cell. In the case of cancer, tumor-derived exosomes have been shown to promote tumor cell proliferation. Now, in a mouse model of melanoma, Peinado et al. report that exosomes derived from highly metastatic tumor cells can influence bone marrow cells, resulting in increased recruitment of provasculogenic bone marrow progenitors to sites of metastasis, increased primary tumor growth and metastatic spread.