Recently, Bobrie et al. showed that inhibition of Rab27a in breast cancer cells decreases the secretion of exosomes and MMP-9, resulting in a decrease in primary tumor growth and lung dissemination in vivo, thus further demonstrating that exosome secretion promotes tumor formation and progression and that inhibition of exosome secretion may impede tumor growth [82]. Here, MMP9 is linked to neoplasm.