KERATIN-19 IN THE ADULT HUMAN PROSTATE - TISSUE AND CELL-CULTURE STUDIES

Keratin 19 is found primarily in simple epithelia. In mammary epitheli a, keratin 19 was localized to a subset of luminal cells, suggesting t hat keratin 19-negative cells may be the proliferative compartment of the secretory cell lineage. The structural and functional similarities of prostate and breast led us to examine keratin 19 expression in the prostate. Immunohistochemical studies revealed that keratin 19 expres sion was heterogeneous and frequently occurred in basal as well as in luminal cells of normal, dysplastic, and benign hyperplastic tissues. Keratin 19 was observed in cancer, bur usually in a minority of cells. This was in dramatic contrast to invasive breast cancers, which are r eportedly uniformly positive for keratin 19. Prostatic epithelial cell s cultured from tissues of all histologies expressed keratin 19. In su mmary, keratin 19 does not obviously correlate with any epithelial cel l lineage or phenotype in the prostate.