YBX1 and posterior cortical atrophy: ProMark is a biopsy-based assay that quantifies eight proteins (CUL2, DERL1, FUS, HSPA9, PDSS2, pS6, SMAD4 and YBX1) demonstrated to be relevant to PCa aggressiveness in men with Gleason Score 3+3 and 3+4 [62,63].