PLK2 and neoplasm: Comparing the in vivo and in vitro results, we observed that, while downregulation of ERBB2/ERBB3, MDM4, IGF1R or IRF5 may be direct effects of CDC-EVs on the cancer cells, many others (such as a reduced expression of HIF1A, CTSL, TOP2A or PLK2) are indirect, host cell-mediated effects with a final negative impact on tumor growth.