Lymphangiogenesis and angiogenesis are critical processes for tumor growth, invasion and metastasis.
Angiogenesis has established its role in the development and progression of a variety of malignancies, playing a crucial role in the dissemination of the tumor cells. However, because of the lack of specificity lymphatic endothelial makers that could be used to discriminate between lymphatics and blood vessels, the definite significance of lymphangiogenesis in sporadic colorectal carcinoma (SCRC) was not very clear.
A research article to be published on January 7, 2008 in the World Journal of Gastroenterology (volume 14, issue 1) addresses this question. The research team led by Pr. Xiang Du from Cancer Hospital, Fudan University, has investigated the lymphatic vessel density (LVD) and microvessel density (MVD) in tumoral areas of 132 cases with primary SCRC. Of the 132 cases, 74 were metastatic cases and 58 non-metastatic cases, which were evaluated by immunohistochemistry, using antibodies of D2-40 and von Willebrand factor (vWF) respectively. In addition, the researchers detected them by double labeling immunohistochemistry to prove the specificity of D2-40.
One conclusion reported by the investigators is that the lymphatic vessels and microvessels at central portions of SCRC often had a reticular architecture, with numerous tiny and ill-defined lumina, while those at tumor borders had large and open lumina. The LVD and MVD were both obviously higher in the cases of colorectal carcinoma with metastasis than in cases without metastasis. For each one lymphatic vessel increased, there was a 1.45-fold increase in the risk of metastasis in SCRC, and for each one microvessel increased, there was a 1.11-fold increase. The specificity and sensitivity of LVD in predicting metastasis or non-metastasis in SCRC were both higher than LVD.
Another conclusion is that high LVD, high MVD, co-accounting of high LVD and high MVD were associated with patients' poor disease-free survival and co-accounting of LVD and MVD was an independent prognostic factor of colorectal carcinoma.
In addition, double labeling immunohistochemistry showed D2-40 immunoreactivity was specific for lymphatic vessels.