[Alpha2-macroglobulin in various pathological conditions of the prostate]

An immunohistochemical study of 10 normal prostates and 100 prostates with tumors showed the presence of alpha-2-macroglobulin (AMG)--an inhibitor of prostatic specific antigen (PSA)--in both normal organ and its tumor. In normal organ, AMG is located in the cells lining the ducts, while in the tumor tissue it is visualized in tubular structures and in parts of undifferentiated carcinoma. AMG is also found in stromal cells and in walls of vessels. Intensity of AMG immunohistochemical response in patients treated with antiandrogen in some cases increased. Intensity of reaction is decreasing when PSA concentration in the blood is very high. The authors suggest that AMG in the prostate is not only PSA inhibitor but also modulator of cell receptors influencing proliferative activity of tumour cells.