Keratin patterns in prostatic hyperplasia and adenocarcinoma.

Keratin patterns in benign prostatic hyperplasia and prostatic adenocarcinoma were evaluated using frozen and formalin-fixed tissue. Five different commercially available antibodies were used. In frozen tissue basal cells of benign acinic and ductal structures stained with PKE, and to a lesser degree with MCA 144, CAM 5.2 and RCK 102. Luminal cells stained with MCA 144, CAM 5.2, RCK 102 and to a lesser degree with PKE. In formalin-fixed tissue basal cells stained exclusively with Z622, predominantly with PKE and RCK 102, and to lesser degree with MCA 144 and CAM 5.2. Luminal cells stained with MCA 144 and CAM 5.2 and to some degree with PKE and RCK 102, while Z622 stained luminal cells of ductal epithelium weakly, but acinic cells not at all. Luminal phenotype dominated in prostatic adenocarcinomas which were stained with MCA 144 and CAM 5.2 irrespective of differentiation, and independently of whether frozen or formalin-fixed tissue was used. However, the different keratin phenotype of benign and malignant prostatic epithelium depends to some degree on the immunohistochemical procedures used. In diagnostic pathology Z622 may be able to separate intraluminal neoplastic lesions from invasive carcinoma, a problem particularly seen when cribriform growth pattern is found.