The cell proliferation of epithelial metaplasia in the prostate gland. An autoradiographic in vitro study.

In 147 autoradiographically examined prostate biopsy cylinders 5.4% squamous metaplasia and 6.0% transitional metaplasia were diagnosed. The average labeling index of squamous metaplasia was 4.3% and corresponded with values from non-keratinizing squamous epithelium in other locations. The labeling index of the transitional cell metaplasia was, in contrary, almost 10 times lower with an average value of 0.29% and corresponded with the values well known for the urothelium of the urinary bladder. Higher labeling indices were observed in 2 cases but these had chronic prostatitis. The autoradiographic results are in good agreement with the ultrastructural findings in which the metaplastic squamous epithelium corresponds with normal squamous epithelium by which the cellular proliferation takes place only in the stratum basale. On the other hand, transitional metaplasia exhibits DNA-synthesizing cells in the superficial cell layers just like in the urothelium.