RAB27B and neoplasm: In general, exosomes are involved in tumor drug resistance in two ways: one is that exosomes transfer key drug resistance proteins (such as Rab27B) or RNAs (such as lncRNAs) to tumor cells to induce or enhance drug resistance; the other is that exosomes can phagocytize drug molecules and excrete them outside the cells to reduce the drug concentration in tumor cells [20, 21].