CAV1 and prostate cancer: To determine if the reduction of bulk exosome secretion was associated with any impact on the secretion of specific exosome-associated markers of prostate cancer, we tested the exosomal fraction of the cell culture supernatant of PC3 cells for the content of two proteins that are both involved in exosome secretion and implicated in prostate cancer progression but otherwise widely different, caveolin 1 [19,20,21] and myosin IC [22,23,27].