ISLR2 and Familial prostate cancer: Of the 20 proteins associated with any prostate cancer outcome, several showed robust associations in only one outcome, including seven that appeared specific to overall prostate cancer (5NTC, CREBL1, INFA14, ISLR2, MMP7, SERPINA1, TNSFRS10B), three that appeared specific to aggressive disease (C4A, C2, TNFRSF6B), and two that appeared specific to early onset disease (SERPINA3, PYY).