Basal cell proliferation in benign prostatic hyperplasia.

Two cell types are found within glandular acini of the human prostate. These basal and secretory cells can be distinguished in the light microscope by their different affinity for toluidine blue. Toluidine blue exhibits a strong affinity for basal cells while secretory cells are poorly stained. In benign prostatic hyperplasia, toluidine blue stained basal cells commonly form a single layer which rests on the basement membrane of glands. Also present are areas where cell layers located nearer gland lumina, thought to be composed of secretory cells, are occupied by cells with a basal like morphology and which exhibit a strong affinity for toluidine blue. The ultrastructure of these cells resembles that of basal cells. Autoradiographic analysis of 3H-thymidine incorporations by hyperplastic prostatic expants in organ culture shows that within glands only basal cells are active in DNA synthesis. The data suggest that basal cells are capable of proliferating and may be a source of secretory cells.