Identification of intermediate cell types by keratin expression in the developing human prostate

The secretory acini of the adult human prostate contain basal, luminal, and intermediate types of exocrine cells. Intermediate cells are thought to play an important role in normal growth and neoplastic transformation. In this study we investigated whether this cell type is present in early stages of prostate development, using keratin antibodies specific for them.

Autoptic tissue from 11 prepubertal and 5 normal adult prostates was immunohistochemically stained with four keratin antibodies capable of specifically detecting basal, luminal, or intermediate cell types.

Morphologically, in fetal prostate cells differentiation was often not evident. However, basally located cells usually displayed a basal-cell keratin-phenotype. Morphologically similar cells with more luminal localization expressed keratins typical of luminal cells, or of intermediate cells.

1) In early stages of prostate development, cells with intermediate keratin-phenotype can be identified. 2) Their large numbers comply with a hierarchical pathway of cellular differentiation from basal to luminal cells. 3) The presence of intermediate cells at such an early fetal age may reflect their regulatory function in prostate development.