L. Buo et al., LOCATION OF PLASMINOGEN-ACTIVATOR (PA) AND PA INHIBITOR IN HUMAN COLORECTAL ADENOCARCINOMAS, APMIS. Acta pathologica, microbiologica et immunologica Scandinavica, 101(3), 1993, pp. 235-241
Both the coagulation and fibrinolytic cascades generate proteolytic en
zymes which appear to be essential for tumor invasion. In the present
investigation adenocarcinomas and normal colon from 14 patients with c
olorectal cancer were studied by immunohistochemistry. The most striki
ng observation was an enrichment of plasminogen activator inhibitor in
the tumor tissue, whereas no such immunoreactivity was detected in th
e biopsies of normal colon. The tumor-host interface was characterized
by a massive accumulation of inflammatory cells, macrophages and T ly
mphocytes. In this area fibrin(ogen) immunoreactivity as a sign of loc
al activation of the coagulation cascade was also seen. The transition
zone between the tumor and normal tissue was furthermore characterize
d by a marked enrichment of urokinase plasminogen activator immunoreac
tivity. The study strongly indicates that proteases and inhibitors of
the fibrinolytic system may be of great importance in tumor invasion.