IQGAP1 expression was analyzed in: (1) primary prostate cancer, (2) xenografts produced from LNCaP, DU145, and PC3 cells, (3) tumor of PTEN−/− and TRAMP mice, and (4) castration resistant PC (CRPC) produced by LNCaP xenografts and PTEN−/− mice. The gene discussed is IQGAP1; the disease is neoplasm.