Based on a large patient cohort in The Cancer Genome Atlas, expression of eight miR‐455‐5p/‐3p target genes (PIR: P = 0.0137, LRP8: P = 0.0495, IGFBP3: P = 0.0172, DMBX1: P = 0.0175, CCDC64: P = 0.0446, TUBB1: P = 0.0149, KIF21B: P = 0.0336, and NFAM1: P = 0.0013) was significantly associated with poor prognosis of PCa patients. This evidence concerns the gene KIF21B and posterior cortical atrophy.