Aim: Angiogenesis is an important step in the growth of solid malignant tumors. A number of angiogenic factors have been found such as transforming growth factor beta1 (TGF-beta1) and vascular endothelial growth factor (VEGF). However, the roles of TGF-beta1 and VEGF in gastrointestinal carcinogenesis are still unclear. This study was to investigate the expressions of TGF-beta1 and VEGF in gastrointestinal tract malignant tumors, as well as their association with microvessel density (MVD). At the same time, we also observed the localization of TGF-beta1 and its receptor CD105 in gastric malignant tumors.
Methods: The expressions of TGF-beta1 and CD105 were detected in 55 fresh specimens of gastric carcinoma and VEGF and CD105 in 44 fresh specimens of colorectal carcinoma by immunohistochemical staining (S-ABC). TGF-beta1 and CD105 in 55 gastric carcinoma tissues on the same slide were detected by using double-stain Immunohistochemistry (DS-ABC).
Results: Among the 55 cases of gastric carcinoma tissues, 30 were positive for TGF-beta1 (54.55%). The MVD of TGF-beta1 strong positive group (++ approximately +++ 23.22 +/- 5.8) was significantly higher than that of weak positive group (+17.56 +/- 7.2) and negative group (- 17.46 +/- 3.9) (q=4.5, q=5.3207, respectively, P<0.01). In the areas of high expression of TGF-beta1, MVD and the expression of CD105 were also high. Among the 44 cases of colonic carcinoma tissues, 26 were positive for VEGF (59.1%). The expressions of both VEGF and CD105 (MVD) were related with the depth of invasion (F=5.438, P<0.05; F=4.168, P=0.05), lymph node metastasis (F=10.311, P<0.01; F=20.282, P<0.01) and Dukes stage (F=6.196, P<0.01; F=10.274, P<0.01), but not with histological grade (F=0.487, P>0.05). There was a significant correlation between the expression of VEGF and CD105 (MVD) (r=0.720, P<0.01).
Conclusion: Over-expression of TGF-beta1 and VEGF acts as stimulating factors of angiogenesis in gastrointestinal tumors. CD105, as a receptor of TGF-beta1, can regulate the biological effect of TGF-beta1 in tumor angiogenesis. MVD marked by CD105 is more suitable for detecting newborn blood vessels.