Loss of high-molecular-weight cytokeratin antigenicity in prostate tissue obtained by transurethral resections

Objective.-Staining of prostatic basal cells for the expression of high-mol ecular-weight cytokeratin has been suggested as a way of distinguishing ben ign from malignant prostate glands. We evaluated the utility of high-molecu lar weight cytokeratin in the diagnosis of malignancy in prostate specimens obtained in various ways. Design.-Prostate tissues obtained from needle biopsies, transurethral resec tions, and total prostatectomies were immunostained with monoclonal antibod y 34 beta E12, an antibody directed against high-molecular-weight cytokerat ins. Results.-Antiserum to high-molecular-weight cytokeratin only stained the ba sal cells in normal glands in 3 (12%) of 25 specimens obtained by transuret hral resection. Other antigens, such as the alternate 10-nm filament protei n vimentin, were unaffected and were detected in 100% of these specimens. H owever, keratin antigenicity in transurethral biopsies could be restored in these specimens by antigen retrieval in a low pH citrate buffer using a mi crowave heat technique. Keratin staining in needle biopsies and total prost atectomies was unaffected. Conclusion.-In summary, our results indicate the technique of transurethral resection results in a specific loss of keratin antigenicity. This limits the utility of anticytokeratin 34 beta E12 in interpreting transurethral re sections without the application of antigen retrieval.