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PROSTATIC DISEASES - PART 2

Bình thường tuyến tiền liệt acini được lót bởi các tế bào cột cao với một lớp tế bào ngoại vi cơ bản (a; H & E). Các lớp tế bào thứ hai là dễ dàng hơn khi nhuộm màu immunocytochemically bởi kháng thể CK 5 +6 đối với cytokeratins trọng lượng phân tử cao (b) | AN ATLAS OF PROSTATIC DISEASES Figure 6 Normal prostatic acini are lined by tall columnar cells with a peripheral basal cell layer a H E . The latter cell layer is more easily seen when stained immunocytochemically by antibody CK 5 6 against cytokeratins of high molecular weight b portions epithelial cells are tall and columnar and perform a secretory role Figure 6 . In the distal ductal portions the epithelial cells are lower in height and exhibit frequent apoptosis programmed cell death . The major function of prostatic epithelium is to elaborate and secrete prostate-specific antigen PSA Figure 7 . Discovered by Wang and colleagues4 PSA is a single-chain glycoprotein consisting of 237 amino acids. The gene encoding PSA is located on chromosome 19 close to the androgen response element ARE . Transcription of this gene is stimulated by the formation of intracellular DHT. Messenger RNA mRNA encoding PSA is then translated into a glycoprotein protease of the kallikrein family . The role of PSA is to liquefy semen after ejaculation and thereby to release spermatozoa to migrate within the female genital tract. Normally only a small proportion 0.1 of the total PSA output is absorbed across the basal cell layer and through the basement membrane into the bloodstream normal serum levels are usually below 4 ng ml Figure 8 . In the bloodstream as one might expect of an active protease the majority of PSA is bound to protein either antichymotrypsin or a2-macroglobulin. A proportion of PSA remains unbound or free . However prostatic diseases especially prostate cancer which result in damage to the integrity of the basal cell layer and basement membrane are associated with PSA levels greater than this value thus PSA is able to serve as a marker for pathological changes5. In addition increasing age in itself is associated with gradual progressive PSA elevation6 Figure 9 perhaps due to increasing leakage of PSA across the basement membrane or due to developing benign prostatic .