Clinical Value Of Vascular Endothelial Growth Factor In Benign And Malignant Pleural Effusion

Pleural effusion is a common problem that can be seen in kinds of benign and malignant diseases, it also can be sorted to exudate and transudate by property, by aetiology it can be categorized to malignant,infectious, the morbidity of malignant effusion is about 20% to 40% in entire effusion. The most common cause of infectious pleural effusion is tuberculosis, malignant effusion is usually seen in pleuralmatastatic carcinoma and mediastinal lymphoma, and the most common cause in pleuralmatastatic carcinoma is lung cancer, then breast cancer and leukemia. Lung cancer with pleural effusion means that the life quality is reducing and the prognosis is relatively poor. The gold standard to make a definite diagnosis is by cytology or by pathology examination. But cytology examination it needs thoracentesis repeatedly, and pathology examination needs to take throacoscopy, both of them are traumatic and mean a heavy burden to patients, so they are not accepted easily. Therefore, to find a convenient and less traumatic index to direct clinical diagnosis and treatment is an urgent problem to solve. Research indicated that VEGF (vascular endothelial growth factor) plays an important role in the mechanism in malignant effusion. Our study is to discuss the relationship between benign and malignant effusion as well as the clinical value of lung cancer with effusion.VEGF is a kind of growth factor that can be seen in vascular endothelial cells particularly, and plays an important role in the growth and the metastasis of most solid tumor, also it has correlation with the formation of pleural metastasis and pleural effusion. VEGF family include VEGF-A,VEGF-B,VEGF-C,VEGF-D,VEGF-E(placenta growth factor, PLGF),VEGF we usually say means VEGF-A ,its gene has been assigned to chromosome 6p21.3, its coding region spans 14kb, is organized in 8 exons, separated by 7 introns. It has 5 isoforms, having respectively121,145,165,189 and 206 amino acids and forming proteins. VEGF165 is the main secretion form, which displays the main biology effect, and our research is to test VEGF165.VEGF is a 34~42 kD homodimeric protein, which is an important multifunctional cytokine that can induce endothelial cell to mitosis by a series of signal conduction mechanism. As a result, vascular endothelial cell begins to division growth and VEGF directly stimulates angiogenesis. In the meanwhile, VEGF increases the vessels permeability especially the capillaries and the venulars, it also induces the plasma to extravasate, to promote the formation of effusion. The strong permeability is regarded as the prominent reason to form effusion.In order to discuss the clinical value of VEGF ,we have done the following clinical research : We measured serum and effusion VEGF levels using a sandwich enzyme-linked immunoadsorbent assay in 34 patients with lung cancer accompanied malignant effusion,in 34 patients with benign effusion, and we measured serum VEGF levels in 30 healthy persons. Three groups had no distinct difference in age, sex (P>0.05).We also measured serum VEGF in 5 patients of the adenocarcinoma before and after chemotherapy. All the data was delivered through means value±standard errand ( x±s). We analyzed the though T test,ANOVA, it has significant difference when P<0.05.In this investigation ,we found that in the serum VEGF levels in lung cancer with malignant effusion,benign effusion and healthy control , the difference was significantly, malignant effusion group had a higher level than that of benign group, and the benign group was higher than healthy control group, F=25.374,P<0.01.The effusion level of VEGF is also significantly between benign and malignant effusion. The level of malignant effusion was higher than that of benign effusion. t=0.236, P<0.01. At the mean time we found that empyema group has a higher level in serum and effusion, respectively 88.07±15.54 pg/ml, 1371.29±656.80 pg/ml, which are quite similar with lung cancer(in serum t=0.228,P=0.821; in effusion t=1.108,P=0.276). But the clinical symptom of empyema is very easy to distinguish with lung cancer, and its effusion is easy to diagnosis visually. After we removed this interference, we found that it was much more significant between the malignant and the benign effusion (P<0.001). But in this investigation the number of empyema was so few that whether the level has statistical significance between empyema and malignant effusion needs a larger scale experiments to analysis. The most common reason of benign effusion is caused by tuberculous, but tuberculous effusion and malignant effusion is not easy to distinguish before we get the cytology or pathology examiation, so we measured 15 tuberculous and 34 malignent patients'serum and effusion, as a result we found that both of them had significant difference, the level of malignant effusion was higher than that of tuberculous. (in serum t=2.949,P<0.05;in effusion t=2.108,P<0.05). We also found that serum and effusion in different pattern of lung cancer had no difference, in serum F=0.465,P>0.05,in effusion F=0.321,P>0.05. We also divided the malignant group into two groups ,18 patients without initial treatment in group one who had a distant metastasis was in stageⅣ,and 16 patients without initial treatment in the other group did not had a distant metastasis which was in stageⅢb. The result was that the VEGF level of group one was higher than group two both in serum and effusion. (in serum t=2.292,in effusion t=2.516, P<0.05). Also we measured serum and effusion VEGF level in 5 of the malignant patients before and after chemotherapy, because after treatment there are very few patients to thoracentesis, only 2 of them, we did not analysis the effusion before and after treatment. But in serum we found that the level was decreasing apparently,t=3.447,P<0.05. But because of the number of the sample , we should do more samples to analysis the confidence.In conclusion, it is useful to distinguish benign and malignant effusion with measuring serum and effusion VEGF level, and the level in serum and effusion maybe used for the lung cancer to diagnosis the disease stages. The VEGF level in serum may be used for the observation of treatment and the prognostic evaluation. VEGF level is higher in malignant pleural effusion than that in tuberculous effusion both in serum and pleural effusion, so it can be an index to distinguish them.