Role of fibrinolysis and α2-macroglobulin in growth of primary adenocarcinoma and rectal polyps.

Abstract

e15093 Background: An important role in tumor angiogenesis induction is played by hydrolytic systems, in particular plasmin one which provides degradation of the extracellular matrix, activates growth factors and metalloproteinases. Our purpose was to analyze the tissue fibrinolytic system and α2-macroglobulin (α2M) in primary adenocarcinoma (PA) and polyps (P) of the rectum (R). Methods: Tissues of tumors (РА, G2, T2-3N0M0, 42-73 years) and their perifocal zone (PZ) in R (n = 24) and Р (n = 27) were studied by ELISA; the result was calculated per 1 mg of tissue. Results: Resection line (RL) tissues contained levels of tРА antigen and its active form (tРА-Ag and tРА-act) 6.7 and 33.8 times higher than prourokinase and urokinase levels (uPA-Ag and uPA-act). RL tissues in P did not differ significantly from R tissues at PA resection. uPA-act in PA was higher than in RL by 3.2 times, uPA-Ag - 8 times higher, tРА-act - 2.3 times lower; tPA-Ag was similar to RL tissue values. Plasmin-α2-antiplasmin complex (PAP) in PA was 1.4 times higher than in RL. Plasminogen (PG) in PA was 1.5 times lower than in RL (p < 0.01). Activity of α2M in PA and RL did not differ. PAP and α2М in PA PZ were similar to RL, and PG did not differ from PA. Other indices were between tumor and RL levels. P tissue did not show changes in uPA; tPA-act activity was 1.3 times lower than in RL, and tPA-Ag 1.3 times higher (p < 0.01). PAP in tissues of 88.2% P was 1.5 times higher than in RL and 1.7 times lower than in PA. PG and α2М were similar in P and RL. PAP in PZ of P was 2.3 times higher than in RL and 1.5 times higher than in PA PZ. PG in P PZ was 1.4 times lower than in RL (p < 0.01). α2М activity in P PZ was higher than in RL and P by 5.4 times on average. uPA in P PZ did not differ from RL; tРА-Ag and tРА-act were higher than in RL by 1.5 and 1.9 times and exceeded P by 2.1 and 1.5 times (p < 0.01). Prevalence of uPA, activation of PG in PA and its PZ indicated degradation of the extracellular matrix compared with the corresponding P tissues. Conclusions: The role of R tumor PZ as a "metabolic" tumor field in neoplasm progression was confirmed. Activation of fibrinolysis in PA and its PZ with a deficiency of inhibitors stimulates the migration and proliferation of cells. Increasing tРА, РАР and α2М in PZ of polyps has a protective effect.