Our recent studies showed cancer exosomes can act to modulate stromal cell fate, driving fibroblast to myofibroblast differentiation, in a manner requiring exosomally-tethered TGFβ1 [28], and that such myofibroblasts had potent angiogenic and tumour promoting properties in vivo; effects that were lost when using Rab27a knockdown cancer cells [29]. Here, RAB27A is linked to cancer.