VEGF is a client protein of Hsp90 (ref. 49), and immunofluorescence experiments show that Hsp90 localizes with VEGF in MVs generated by various breast cancer cells, including primary tumour cells cultured from PDXs (Fig. 5a, see arrows), as well as MDAMB231 cells (see Fig. 6a, below), but not in cells in which VEGF expression was eliminated by RNAi (Supplementary Fig. 5A). The gene discussed is VEGFA; the disease is breast cancer.