Metastatic behavior of prostatic tumor as influenced by the hematopoietic and hematogenous factors.

Metastasis represents a hallmark of the tumor cell's escape from normal cellular behavior to acquired invasive and migratory style. Metastasis of prostate cancer (Pca) depends upon the interplay of a series of hematogenous and hematopoietic factors. We investigated the role of some of those factors implicated in the dissemination process in two separate sublines of adenocarcinoma of the prostate. Our data revealed that (1) the urokinase plasminogen activator activity was significantly higher in R3327-AT3, an aggressive metastatic tumor, as compared to R3327-G, a nonmetastatic tumor of the prostate, (2) the concentration of platelets decreased, and the platelet-aggregating activity increased significantly when the platelets were reacted with exogenous aggregating agents and tumor effusions to suggest that activation of the hemostatic system could protect tumor cells from immunosurveillance and facilitate the process of hematogenous dissemination, and (3) transferrin, which has been reported to have a growth-promoting effect on Pca, did not show any appreciable effect on tumor growth but did alter the level of in vitro adherence which possibly could lead to better attachment and increased invasive behavior of tumor cells.