Study On Relationship Between Expression Of VEGF-C,PTEN And Lymphangiogenesis And Lymph Node Metastasis In Non-Small Cell Lung Cancer

Background Primary bronchoginic carcinoma(lung cancer) is the malignant tumor originates the epithelium mucosae or glandular organ of the bronchus. Of about 80% lung cancer is non-small cell lung cancer(NSCLC). Incidence rate and death rate are rising rapidly.Since the 1980,s, lung cancer has become the world's highest incidence of malignant tumors.Early diagnosis of lung cancer is very difficult.65% of patients has become advanced stage when they have a clear diagnosis. Relapse and metastasis are the main reasons for its death. Lymph node metastasis is the main way to NSCLC proliferation, but also the main factors to the impact of radical surgery and prognosis. For most of human malignant tumor, tumor cells through lymphatic spread to local lymph nodes are an important indication of the clinical stage. In the tumor matrix of lymph node metastasis, lymphatic proliferation and expansion can often be found , but its molecular mechanism has not yet been fully clarified, and the role of the formation of lymphatic vessels to lymph node metastasis remains unclear.In the past few decades,because of the lack of specific lymphangiogenesis factor and specific lymphatic marker factor, the study on lymph node metastasis makes less progress,and most of them are focused on the vascular system.In recent years,the vascular endothelial growth factor C(VEGF-C) and its receptor VEGFR-3 are found,and VEGF-C is known that it is a relatively specific lymphatic endothelial growth factor.The expansion of lymphatic endothelial to promote the formation of lymphatic vessels is occurred after VEGF-C and VEGFR-3 combine together,and thus to study the mechanism of lymph node metastasis has opened new avenues.Phosphatase and tensin homolog deleted from chromosome 10(PTEN) is the one and only tumor suppressor gene with lipid phosphatase and protein phosphatase double activety. PTEN involved in apoptosis and cell cycle regulation,and its mutation can lead to tumor growth.Literature reports a variety of human tumors have PTEN mutation and deletion,but it is particularly evident in advanced lung cancer with lymph node metastasis.Lymphatic vessel density(LVD) is a quantitative measure of lymphangiogenesis,which has been showed to be an important parameter of the biological behavior of various malignant tumors.Up to now,there have been few reports on the expression of VEGF-C,PTEN and their correlations with lymphangiogenesis in NSCLC.Objective In this study,a new lymphatic endothelial markers"podoplanin"is used to detect lymphatic tissue of NSCLC,and LVD measures lymphangiogenesis express.To investigate the expression of VEGF-C and PTEN in NSCLC,and their correlations with the lymphangiogenesis and other clinical pathophysiological characteristics of NSCLC,in order to provide sufficient evidences for anti-lymphangiogenesis therapy for NSCLC.Methods 68 patients with primary NSCLC were included in this study.68 tumor tissues resected from each patient and 30 normal lung tissues from 30 patients were collected.All the samples were fixed in 10% neutral formalin and embedded with paraffin.Immunohistochemical using streptavidin peroxidase conjugate method was performed to estimate the expression of VEGF-C,PTEN and podoplanin. Statistical analysis with t-test,Chi-square,Fish,s exact probability test and linear correlation were performed to analyze the expression difference between tumor tissues and normal lung tissues.Furthermore,the correlations among VEGF-C,PTEN,LVD and other clinical pathophysiological characteristics were also analyzed.Results1 The VEGF-C-positive rates were 83.80%(57/68) in NSCLC group and 16.70%(5/30) in normal lung tissues.There was a significant difference between them(x~2=40.396 P<0.01).The PTEN-positive rates were 42.60%(29/68) in NSCLC group and 86.70%(26/30) in normal lung tissues. There was a significant difference between them(=30.077,P<0.01).The LVDs were 20.30±6.01 in NSCLC group and 10.55±4.90 in normal lung tissues.The difference between them was also significant (t=7.800,P<0.05).2 The VEGF-C-positive rates were 90.30%(28/31) in adenocarcinoma, 80.80%(21/26) in squamous carcinoma and 72.70%(8/11) in adenosquamous carcinoma.There was no significant difference among them.3 The VEGF-C-positive rates were 54.50%(12/22) in high-middle differentiation group and 97.80%(45/46) in poorly differentiation group.There was a significant difference between them( x~2=17.491,P<0.01).The PTEN-positive rates were 86.40%(19/22) in high-middle differentiation group and 21.70%(10/46) in poorly differentiation. The difference between them was also significant ( x~2=25.411,P<0.01).4 In stageⅠ+ⅡandⅢof NSCLC, the positive rates of VEGF-C were 60.00%(12/20) and 93.80%(45/48),the positive rates of PTEN were 80.00%(16/20) and 27.10%(13/48).The difference of VEGF-C and PTEN expression between stageⅠ+ⅡandⅢwere significant respectively(x~2=6.016,P<0.01;x~2=16.162,P<0.01).5 In the group with lymph node metastasis and the group without lymph node metastasis, the positive rates of VEGF-C were 88.10%(52/59) and 55.60%(5/9),the positive rates of PTEN were 37.30%(22/37) and 88.90%(8/9).The differences of VEGF-C and PTEN expression between the two groups were significant respectively(=3.946,P<0.05;x~2=6.470,P<0.05).6 The LVDs in the VEGF-C-positive group and the VEGF-C-negative group were 22.31±4.20 and 17.90±4.80 respectively,the difference was significant (t=3.117, P<0.05);The LVDs in the PTEN-positive group and the PTEN-negative group were 16.10±5.30 and 21.10±4.80 respectively,the difference was significant (t=4.062, P<0.05);The LVDs in the group with lymph node metastasis and the group without lymph node metastasis were 21.90±5.90 and 16.51±5.50,the difference between them was also significant((t=2.573,P<0.05)).7 There was significant correlativity between the expressions of VEGF-C and PTEN in NSCLC(r=-0.2672,x~2 =17.818,P<0.01).Conclusions1 The expressions of VEGF-C and PTEN in NSCLC tissues are higher and lower respectively than that in normal lung tissues.VEGF-C and PTEN expressions are significantly associated with lymph node metastasis,TNM stage and tumor differentiation,but not associated with the histology type of NSCLC.2 The LVDs of tumor tissues in NSCLC were higher than that of normal lung tissues. VEGF-C and PTEN expressions in NSCLC tissues correlate with LVD,which indicates that VEGF-C maybe positively regulate the tumor lymphangiogenesis and PTEN maybe negatively regulate the tumor lymphangiogenesis in NSCLC. VEGF-C and PTEN expressions can be used as the prediction of NSCLC patients with lymphangiogenesis and lymph node metastasis.3 There is significant negative correlation between expressions of VEGF-C and PTEN in NSCLC.