Catenin/E‐cadherin complex proteins play an important role in cell–cell adhesion with decreased expression correlating with adverse prognostic variables in several human malignancies.

Archival formalin fixed, paraffin embedded (FFPE) sections from 118 prostatic adenocarcinomas (PACs) were immunostained by an automated method (Ventana Medical Systems, Tuscon, AZ) using monoclonal antibodies to catenins α and β, p120 CTN, and E‐cadherin proteins. Immunoreactivity was semiquantitatively graded, and results correlated with traditional prognostic parameters. In a subset of 10 randomly selected cases, E‐cadherin gene promoter methylation status was determined on FFPE tissues using sodium bisulfite/hydroquinone DNA modification and polymerase chain reaction (PCR) with methylation specific primers (CpG wiz E‐cadherin methylation assay; Intergen Co., Purchase, NY).

Decreased expression of α‐catenin (17%), β catenin (4%), p120 CTN (45%), and E‐cadherin (25%) proteins was noted in PACs with downregulation of each protein correlating with high tumor grade (P = 0.01–0.0001). In addition, p120 CTN and E‐cadherin expression levels correlated with pathologic stage (P = 0.05; P = 0.02), aneuploidy (P = 0.001; P = 0.0001), and α‐catenin with aneuploidy (P = 0.0001). p120 CTN loss also correlated with preoperative serum prostate specific antigen (P = 0.05). Two of 10 cases featured no evidence of E‐cadherin gene promoter methylation by PCR and both cases retained expression of E‐cadherin protein on immunohistochemistry. Of the 8 cases that showed E‐cadherin methylation, 5 (68%) featured loss of expression of the protein on immunohistochemistry (P = 0.11). There was no correlation between E‐cadherin methylation and adverse prognostic variables.

Decreased expression of catenin/E‐cadherin complex cell adhesion proteins is associated with aggressive phenotype in prostatic adenocarcinoma. E‐cadherin gene promote methylation is a common event in prostate carcinoma but does not appear to bear prognostic significance in the subset of cases analyzed. Cancer 2001;92:2786–95. © 2001 American Cancer Society.