Heterogeneous expression of E-cadherin and p53 in prostate cancer: clinical implications. BIOMED-II Markers for Prostate Cancer Study Group.

Histologic grade and tumor volume are markers of malignant phenotype. More objective markers, however, have been sought for needle biopsy specimens. The aim of this study was to evaluate how immunohistochemical expression of the potential prognostic markers E-cadherin and p53 in biopsy specimens relates to the expression of these markers in prostatectomy specimens. Therefore, we analyzed 47 prostatectomy specimens and their preoperative biopsy specimens. Fixation of surgical specimens and the immunohistochemical assay for both E-cadherin and p53 expression was optimized. All paraffin blocks containing areas of carcinoma were submitted for immunohistochemical analysis. The prevalence of abnormal p53 immunoreactivity was only 11%. In addition, abnormal p53 expression was virtually restricted to cases that were already identified as having a poor prognosis on the basis of the large volume and the high grade of their carcinomas. In 28% of the cases, we found abnormal immunoreactivity for E-cadherin. These cases revealed considerable heterogeneity in topographic distribution of abnormal expression. The level of sensitivity to the detection of abnormal E-cadherin expression or abnormal p53 in the prostatectomy specimen was 15% and 60%, respectively. In view of the inherent heterogeneity of E-cadherin expression and the low prevalence of abnormal p53 expression, we question the use of these markers for prognostic purposes in needle biopsy specimens. Unless representative sampling by needle biopsy can be assured, the use of E-cadherin expression will be of most value in prostatectomy specimens.