Relationship Between Lymph Vessels With Tumor-associated Macrophages In Colorectal Carcinoma Tissues

Objective: Distant metastasis of colorectal carcinoma is a significant factor that result in failuer of treatment and death through blood and lymphatic metastasis. Relationship between blood vessels and tumors has been in-depth studied, but for a long time, lack of the high sensitivity and specificity marker that identify lymphatic microvessel leaded to researches of lymphangiogenesis lag behind that of blood vessel angiogenesis. D2-40 is a novel monoclonal mouse anti-lymphatic endothelial marker antibldy. It doesn't mark the blood vessel endothelial cell and possesses high sensitivity and specificity, so it may use in the lymph vessel counting. Macrophage that infiltrate into the tumor are known as tumor-associated macrophage(TAM). It plays an important role in tumor growth, invasion, metastasis and recidivism. Recently, researches on the relationship between TAM and blood vessel angiogenesis are extensive, which consider that TAM is able to promote blood vessel angiogenesis. However, researches on the relationship between TAM and lymphangiogenesis are insuffice, one of possible reasons is lack of the specificity antibldy that mark lymph vessel. The purpose of this study was to investigate the expression of lymph vessel and tumor-associated macrophage in benign and malignant tissue of colorectal tumor to research their relationship and try to approach mechanism of lymphangiogenesis.Methods: Fourty-eight specimens resected from patients with benign or malignant colorectal tumor in The Second Affiliated Hospital of GuangZhou Medical University between 1998 and 2000. Another 13 specimens of colorectal normal tissue regard as the control group. All specimens were confirmed by pathology.They were immunohi- stochemically stained by anti-lymphatic endothelial marker D2-40 monoclonal antibody and anti-macrophage marker CD68 monoclonal antibody.Refered to the method of Weidner and Leek, we counted the number of D2-40 and CD68.Statistical analyses were carried out using SPSS 11.5 statistical packages. Counts data are shown as means±SD. Difference and correlation between two groups were determined by t–test and spearman correlation .Statistical significance was accepted at the P<0.05 level.Results: Cells staining for D2-40 assume yellow or brown granules located on cell membrane and mainly distribute in tissues surrounding carcinoma cells and less present in normal tissues and and cancer nest. Lymph vessel stained by D2-40 show kind of circular and funicular state. CD68-positive macrophages also express yellow or brown granules in cytoplasm and distribute between the normal tissue and cancer nest.The counts of LV in colorectal carcinoma and colorectal benign tumor are obviously higher than those in control group(P<0.001). The counts of LV in colorectal carcinoma with lymph node metastasis is more than those in colorectal carcinoma without lymph node metastasis. The number of TAM of colorectal carcinoma is more than those of colorectal benign tumor. In colorectal carcinoma, the number of LV was positive-correlated with the number of TAM(r=0.58,P<0.01); In colorectal carcinoma with lymph node metastasis, the number of LV was significantly positive-correlated with the number of TAM(r=0.66,P<0.01); In colorectal carcinoma without lymph node metastasis, colorectal carcinoma the number of LV was positive-correlated with the number of TAM(r=0.56,P<0.01); In colorectal benign tumor, the number of LV was obviously negative correlated with the number of TAM(r=-0.66,P<0.01).Conclusion: There are lymph vessel angiogenesis in benign and malignant tissue of colorectal tumor. TAM possible to promote lymph vessel angiogenesis and play the influential role in the lymph node metastasis in colorectal carcinoma. TAM possibly suppresses the lymph vessel angiogenesis in colorectal benign tumor.