RAB27A and neoplasm: In fact, knockdown of Rab27a suppresses both in vitro cell growth of melanoma cells with Rab27a gene amplification (Akavia et al., 2010) and in vivo tumor growth of melanoma cells where Rab27a-dependent exosome secretion educates bone marrow-derived cells to support tumor growth and metastasis (Peinado et al., 2012).