Cell adhesion molecule expression has been linked to disease outcome in prostatic adenocarcinomas (PACs). We evaluated the coordinated expression of catenin-related proteins, E-cadherin, N-cadherin, and CD44s in PACs. Archival sections from 112 PACs were immunostained by an automated method (Ventana Medical Systems, Tucson, AZ) using monoclonal antibodies to alpha- and beta-catenins, p120CTN, E-cadherin, N-cadherin, and CD44s proteins. Immunoreactivity was semiquantitatively scored, and results were evaluated for association between these markers. Staining results were also correlated with tumor grade, stage, ploidy, preoperative serum PSA, and postoperative biochemical disease recurrence. Decreased expression of alpha- and beta- catenins, p120CTN, E-cadherin, and CD44s proteins (range, 5% to 49%) was noted in PACs, and downregulation of each of these proteins correlated with high tumor grade (P =.02 to.0001). Although loss of E-cadherin and p120CTN each correlated with stage (E-cadherin, P =.02; p120CTN, P =.02) and ploidy (E-cadherin, P =.0001; p120CTN, P =.004), downregulation of CD44s correlated with ploidy (P =.002), serum PSA (P =.005), and postoperative disease recurrence (P =.02). N-cadherin was positive in only 5% of PACs and did not correlate with any prognostic parameters. alpha-Catenin downregulation correlated with decreased expression of E-cadherin (P =.0001). Additionally, decreased expression of each of these 2 proteins respectively correlated with loss of beta-catenin (P =.0001 and.004), p120CTN (P =.005 and.001), and CD44s (P =.008 and.01). beta-Catenin expression levels correlated with p120CTN (P =.01). A trend for co-downregulation of CD44s and p120CTN and of CD44s and beta-catenin was observed. In conclusion, the significant association between decreased expression of various members of the CAM family of proteins supports their collective role in mediating cell-cell adhesion. Altered expression of these proteins may be of prognostic value in patients with prostate cancer.