Extracellular matrix in prostate adenocarcinoma: Changes in the glycoprotein component of the basement membrane

This study was designed to assess the condition of the basement membrane of archival prostate carcinoma tissue when adjacent to tumor cells of varying degrees of malignancy, using a simple staining technique. Tissue was obtained from 87 patients with untreated prostate cancer. Tissue was randomly selected from four patients from each of four Gleason grades of 2, 3, 4, and 5. Tissue was fixed in 10% formalin and routinely processed. Sections were freshly cut from paraffin blocks and slides were subjected to the periodic acid-Schiff (PAS) reaction. Gleason grades 2, 3, 4, and 5 were visualized. As the Gleason grade increased, the intensity of staining, density, and thickness of the gel-like basement membrane decreased. With the increasing Gleason grade, as seen by the PAS stain, the basement membrane glycoprotein decreased in its density and thickness with increased fragmentation, which suggested that the basement membrane would be so modified by the tumor cells to allow the tumor to spread locally. The breakdown of the basement membrane is probably a consequence of increased intratumor pressure, certain proteolytic enzymes, and increased cell motility associated with increased degree of malignancy.