STAT3 and cancer: Along similar lines, PD-L1, Survivin and Integrin-β5 have already been found in vesicles isolated from cancer patients [48–51], SPARC, STAT3 and activated EGFR (EGFR_pY1173), have been described as predictors of response to targeted therapy [52–54] while IL-6 is known to promote prostate tumorigenesis and progression to aggressiveness [52, 55].