Importantly, many clinical trials involve cancer-derived EVs as a biomarker for cancer prediction, stage, prognosis, diagnosis and therapeutic treatment response [18,36], considering that tumor cells exhibit an increased and dysregulated release of EVs, caused by the activation of oncogenic signaling pathways or altered Rab GTPase activity (e.g., Rab27a/b) [40,41]. Here, RAB27A is linked to cancer.