Histopathologic Characteristics Of Blood And Lymphatic Vessels In Epithelial Gastrointestinal Tumors And Their Significance

[Objective] To investigate the expression of CD34,D2-40 by combining to detect them and the expression of Vascular endothelial growth factor (VEGF),Vascular endothelial growth factor-C (VEGF-C) in early gastrointestinal epithelial tumors. To oberve the distributing characteristics of blood and lymphatic vessels in early gastrointestinal epithelial tumors; to discover the way to distinguish blood vessel invasion (BVI) and lymphatic vessel invasion (LVI) and their significance; and furthermore, to explore the expression characteristics of VEGF and VEGF-C and their clinical significance.[Background] Gastrointestinal cancers were malignant tumors that threaten human health. Both stomach and colorectum were most important digestive and absportation organs, with abundant of blood and lymph vessels. Blood and lymph vessels are two of the most important factors in microenvironments that are essential requirements for cancer development, progression and metastases. Historically, studies of lymphatic vessels and blood vessels had been hampered by the absence of specific markers. It was often difficult to distinguish between lymphatic vessels and blood capillaries on haematoxylin and eosin (H&E) stained slides. Recently, it has been shown that the D2-40, a novel monoclonal antibody, was sensitive and specific antibody for the detection of lymphatic endothelium. Although the angiogenesis and lymphangiogenesis in gastrointestinal cancers had been investigated by many studies, their distribution characteristics in gastrointestinal intramucosal neoplasia were not well addressed. Although vessels invasion were frequently occurred in gastrointestinal tumors, there was no consensus on the criteria of accessing vessels invasion, especially on distinguishing blood vessel invasion and lymphatic vessel invasion.[Methods] Biopsies were taken from 37 patients with stomach intramucosal carcinoma, 28 patients with colorectal intramucosal neoplasia, 19 patients with stomach cancers invaded through mucosal muscles, and 11 patients with colorectal cancers invaded through mucosal muscles. Tissues around and in the center of the tumor of all patients, as well as normal tissues more than 3 cm far from tumor of 52 patients, were taken for the study. We evaluated the blood microvessels density and lymphatic microvessels density by immunostained with monoclonal antibodies of CD34 and D2-40 in 37 patients with stomach intramucosal carcinoma and 28 patients with colorectal intramucosal neoplasia. Vessels with endothelial cells labelled by CD34 but not by D2-40 were recognized as blood vessels; and vessels with endothelial cells labelled by both CD34 and D2-40 were recognized as lymphatic vessels. Blood microvessel density (BMVD) and lymph microvessel density (LMVD) were counted as describe by Weidner et al. Blood vessel invasion (BVI) and lymphatic vessel invasion (LVI) were accessed as describe by Van den Eynden et al.[ Results ] Positive staining of CD34 showed brown particles located in cytoplasm and cell membranes. And positive staining of D2-40 showed brown particles located in cytoplasm. We did not found significant difference in BMVD between peritumor tissues and normal tissues (P=0.166), despite of whether tumor located in stomach (P=0.101) or colorectal (P=0.651). Also, there was no significant difference in BMVD in peritumor tissues between stomach tumors and colorectal tumors. However, the BMVD of normal tissues was higher in stomach than in colorectal (P=0.001). Intratumoral lymphatic vessels were rare, and scattered intratumoral lymphatic vessels were seen in tumor stroma with narrow or collapsed lymphatic spaces. Most lymphatic vessels were located within the peritumor tissues and normal tissues. The LMVD was significant higher in peritumor tissues than in corresponding normal tissues in gastrointestinal neoplasia (20.87 vs. 14.56, P=0.003). The increase of LMVD in peritumoral tissues was independent of whether tumor located in stomach (P=0.044) or colorectal (P=0.018). However, we have not found significant difference of LMVD in peritumoral tissues between stomach and colorectal tumor (P=0.970), as well as between normal stomach tissues and normal colorectal tissues (P=0.868). Patients with positive lymph nodes have a higher BMVD compared with patients with negative nodes (P=0.047). However, there was no significant difference in LMVD in peritumoral tissues between patients with and without lymph nodes metastases (P=0.277). BVI correlated with LVI significantly (P<0.001). IHC staining detected more vessel invasion than HE staining (P<0.001). The depth of invasion of tumor correlated significantly with BVI (1.5% vs. 33.3%, P<0.001) and LVI (7.7% vs. 40.0%, P<0.001). The statues of lymph nodes correlated significantly with BVI (6.9% vs. 26.1%, P=0.022) and LVI (6.9% vs. 52.2%, P<0.001). Compared with patients with gastrointestinal intramucosal tumors and patients without lymph node metastases, the expression level of VEGF and VEGF-C were significantly increased in patients with tumor invaded through the submucosa and in patients with lymph node metastasis.[ Conclusions and significance ] The lymphatic microvessels density washigher in peritumoral tissues than in corresponding normal tissues in gastrointestinal intramucosal neoplasia. The blood microvessels density in peritumoral tissues was higher in patients with lymph node metastases than in patients without lymph nodes metastases. These results suggested that blood and lymphatic vessels play different roles in the development and progression of gastrointestinal cancers. Based on the phenomena, a more targeted therapy should be developed. The sensitivity and specificity of IHC staining were higher than HE staining in detecting vessel invasion. BVI and LVI seem to be prognostic factors to gastrointestinal cancers. The expression of VEGF and VEGF-C were associated with the invasion depth and statues of lymph node metastases.