VEGFA and neoplasm: The combination treatment of bevacizumab with a Hsp90 inhibitor, 17‐N‐allyamino‐17‐demothoxygeldanamycin (17AAG), can restore the bevacizumab sensitivity of EV surface VEGF and inhibit tumour growth in a breast cancer patient‐derived xenograft model through 17AAG localizing to microvesicles (MVs), binding VEGF90K and releasing this VEGF, thus increasing the efficacy of bevacizumab.39