Expression And Significance Of VEGFR-3,LYVE-1 And Nm23 In Gastric Carcinoma

In recent years, with the identification of lymphatic endothelial growth factor-C (VEGF-C), VEGF-D and lymphatic endothelial markers including lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1), VEGF receptor-3 (VEGFR-3), glomerular podocyte membrane mucoprotein (podoplanin) and a homeobox transcription factor (Prox-1), lymphangiogenesis has become one of the main areas in the field of tumor metastasis study. It has been demonstrated that lymphangiogenesis induced by VEGF-C/VEGF-D plays a crucial role in promoting tumor cell dissemination to regional lymph nodes in animal models. Human tumor lymphangiogenesis has also been identified in many solid tumors including breast cancer, melanoma, and head and neck carcinoma. Tumor lymphangiogenesis data, however,are often controversial with focus on two questions: 1. Do functional lymphatic vessels exist within tumors ? 2. Does intratumoral or peritumoral lymphangiogenesis play the dominant role in tumor metastasis? In the present investigation, the relationships between the expression of VEGF-C/VEGFR-3, lymph node metastasis and prognosis have been studied in lymphangiogenesis in gastric cancer. Few data on the impact of lymphangiogenesis on the prognosis of gastric cancer in patients exist so far. Further studies on the mechanism and significance of lymphangiogenesis in gastric cancer would be of value to provide experimental evidence for anti-lymphangiogenic therapy.Objective To select the most specific lymphatic endothelial marker through comparisons between LYVE-1 and VEGFR-3 for further studies on the mechanisms of intra- and peritumoral lymphangiogenesis and the relevance to various clinical pathological parameters, including the presence of lymph node metastasis and prognosis in gastric cancer.Methods 1. A total of 53 gastric cancer patients with detailed clinical and complete postoperative follow-up records from Feb 11, 1991 to May 22, 1997 were enrolled in this study. Follow-up was made through phone calls, letter inquiries and visits by census register agencies. Operative tissues embedded with paraffin from the 53 patients with gastric cancer and an additional 10 gastric ulcer patients were investigated. No patients were treated with radio-or chemotherapy before surgery.2. The expression of CD34, VEGFR-3, LYVE-1 and nm23 was quantified in 53 paraffin sections of gastric carcinoma and 10 gastric ulcer tissues using immunohistochemistry. Micro-lymphatic vessel density (MLD) and microvessel density (MVD) were measured. The specificity of lymphatic vessel endothelium markers was compared between LYVE-1 and VEGFR-3 and the relationship between the expression of nm23 in the tumor tissues and the occurrence of lymph node metastasis was also determined.3. The clinical significance was studied by analyzing the relationships of peritumoral and intratumoral lymphangiogenesis, various clinical pathological parameters and follow-up data in 53 cases of gastric carcinoma.Results 1. A positive correlation was found between the number of CD34 positive vessels and the number of VEGFR-3 positive vessels (the Spearman rank correlation coefficient r=0. 387 , P=0.003), while a negative correlation was found between the number of CD34 positive vessels and the number of LYVE-1 positive vessels (r=-0.181, P=0.232) , indicating that most VEGFR-3 vessels and few LYVE-1 positive vessels were blood vessels, while most LYVE-1 positive vessels were lymphatic vessels. Thus LYVE-1 showed to be the more specific marker of lymphatic vessel endothelium.2. LYVE-1 positive MLD in peritumoral regions of gastric carcinoma tissues and in lymph node metastasis was significantly higher than in normal tissue and in no lymph node metastasis (P<0. 01) . No significant difference between MLD in normal tissues and in intratumoral regions was observed (P>0. 05) . 3. Univariate analysis suggested that peritumoral MLD, the presence of lymph node metastasis, pathological stage and nm23 expression were prognostic factors for gastric cancer patients (P<0. 01) . Multivariate analysis indicated that peritumoral MLD, pathological stage and the existence of lymph node metastasis were significant and independent prognostic factors in gastric cancer patients, and that high MLD was associated with a poor prognosis.Conclusions 1. LYVE-1 is a more specific lymphatic endothelial marker. It is also suggested that peritumoral lymphangiogenesis might promote lymph node metastasis.2. Peritumoral lymphangiogenesis may play an important role in the onset and progression of gastric carcinoma, while intratumoral lymphangiogenesis may be without effect.3.High peritumoral lymphangiogenesis is a significant and independent factor indicating poor prognosis in gastric carcinoma patients.