Previous studies have found that inhibition of exosome secretion by deletion of exosome secretion regulator Rab27a or NSMASE2, or treatment with exosome secretion inhibitor GW4869, significantly restrain tumour growth and augment the efficacy of immunotherapy in vivo (Poggio et al., 2019; Yang et al., 2018). Here, RAB27A is linked to neoplasm.