RAB27A and cancer: Knockdown Rab27 via RNAi reduced exosome release, tumour growth and the dissemination of metastatic colonies significantly,100 Conversely, overexpression of EPI64, a candidate GAP that is specific for Rab27, could promote exosome secretion in lung cancer cells.101 Exosomes could be internalized by recipient cells through endocytic processes, or directly fusion with the cellular membrane, heparan sulphate proteoglycans have been implicated in this process, and treatment with heparin significantly inhibit exosome uptake by cancer cells.102