Study On Vascular Endothelia Growth Factor Expression In Non-small Cell Lung Cancer And Its Relationship With PET/CT Signs

The growth and metastasis of malignancy are all depended on tumor angiogenesis, which is the result of the elaborate balance between multiplication-stimulating genes and restraining genes existing in blood endothelial cell. This reciprocity are accomplished by forming genes of tumor angiogenesis, and one of them is vascular endothelia growth factor (VEGF). Many scholars pay more attention to VEGF, which is a kind of biological and positive gene participating in tumor angiogenesis .The excessive expression of VEGF can be found in many tumors such as alimentary canal tumor, urinary bladder tumor, hemopoiesis system and respiration tumor, which is the character of malignancy.The positive expression of VEGFcan not only play an important role in the development and proliferation of tumors (including attack and metastasis) but also possess an important value in evaluating pathological classification, radiation therapy and prognosis .VEGF exert its function on by the way of side-excretion.The main function of VEGF is to accelerate the proliferation and transference of vascular endothelial cells, increase the penetrating capability of vascular and restrain the maturity of submission cells in host antigen. The span of VEGF gene is 28kb including seven inners and eight outers; it exits on p21.3 of the sixth chromosome. The family of VEGF includes six numbers: VEGF-A, VEGF-B, VEGF-C, VEGF-D, VEGF-E and placenta growth factor (PIGF). According to the montage mode of VEGFmRNA coding and the number of aminophenols of VEGF albumen , the formation of VEGF can be divided into five kinds of types : VEGF121, VEGF145, VEGF165, VEGF189 and VEGF206. The expression of VEGF is different in different tumors, for example, VEGF121 and VEGF165 are mainly found in the tissues of lung cancer. The biological affections of VEGF in tissues of lung cancer carry out through two special membrane receptors (Flt-1和KDR). KDR is the mainly modulation gene which can accelerate the proliferation of endothelial cells in lung cancer, and it can stimulate the growth of vascular by side-secretion, and the proliferation and metastasis of tumor cell can be stimulated by self-secretion.Inorder to discuss the expression character of VEGF mRNA in non-small cell lung cancer(NSCLC)and analyse the relationship between the expression character of VEGF mRNA and pathologic character, the expression of VEGFmRNA in 56 patients with NSCLC, 20 patients with benign tumors and normal lung tissues were examine by method of RT-PCR. The results show that The results showed that there was no statistical significance expression of VEGFmRNA between different pathological tissue types; there was almost no positive expression of VEGFmRNA in normal lung cancer and benign tumors, but the positive expression of VEGFmRNA in non-small cell lung cancer could be found in 47cases(83.93%). Comparing to patients of clinical stage I and II of NSCLC , the patients of clinical stage III of NSCLS expressed much more VEGFmRNA and the statistical significance could be found between each two groups.The expressiong of VEGF was modulated by many factors, and the most important factor was hypoxygen .The level of VEGFmRNA, protein and its biological characters would be improved under the condition of anoxemia; the others important factors were cancerous-genes, anticancerous- genes and cytogenes. Mutational p53, bFGF, TNF-αand NO et al were positive regulating factors which could improve the expression of VEGF. Because the growth and metastasis of substantial tumors were depended on the neonate of vessels, many scholars payed more and more attention to VEGF for the reason of therapy of anti-angiogenesis. At present, the method of evaluating the tumor was measured the expression of VEGF and MVD by using immuno-histo-chemical methods(SP). VEGF was an important gene in stimulating endothelia cell division and angiogenesis. As a golden standard to tumor angiogenesis, micro-vessel density, (MVD) reflected the degree of tumor angiogenesis. MVD, was highly related to metastasis and recrudescence, and it was an important index reflecting the biological action of malignant. MVD values was a golden standard to tumor angiogenesis, on the other hand , VEGF was an important gene in stimulating the growth of tumor vessels, as a result, the relationship between MVD and VEGF must be correlatively . Lots of investigations had demonstrated that the relationship between the MVD values and expression of VEGF was positively correlative, which was an significant index to reflect the biological action of malignantTo investigate the relationship between the expression of VEGF, MVD and clinical pathologic factors in NSCLC, we examined the expression of VEGF and MVD in 56 patients with were examined using immuno-histo-chemical methods(SP).The result suggested that the positive expression of VEGF, MVD was associated with the differentiating degrees, clinical stages and lymph node metastasis; the expression of VEGF, MVD was not associated with histological types. It maybe a good predictors to evaluate the prognosis of human NSCLC if these two index were examined together.At present, the therapeutic methods that basing on restraining the growth of tumor angiogenesis have entered the clinical experiment period .It would be very important to the guidance of clinical therapy if the status of tumor angiogenesis could be supervised in vivo. Many people have paid more and more attention and investigation to the displaying method of nuclear medical that could present the tumor angiogenesis and the relating mechanism. The most common method of nuclear medical is 18F-fluoro-2-deoxy-D-glucose PET/CT imaging. 18F-FDG is a kind of material that resemble to glucose, and it could be uptake and metabolized by many kinds of malignant cells. The abnormal proliferation of malignant cells have to use the glucose excessively, as a result, a lot of 18F-FDG were gather together in ells. were transferred into the cell by GLUTs existing on cellular membrane. 18F-FDG was phosphated into 6-phosphate-glucose in the cell. The uptake of FDG by the tumor tissues could be measured half-quantified by standard uptake value (SUV). One investigation approved recently that the GLUTs and VEGF were increasing cooperatively under the condition of anoxemia .The manifold of GLUTs in tumors meant the uptake of FDG would manifold either, and the SUV of lesions would improved cooperatively.To investigate the relationship between the expression level of VEGF and the uptake of 18F-FDG in NSCLC, The expression of VEGF and micro-vessel density (MVD) in 56 cases were estimated by statistical analysis with PET/CT signs. The relationship between the expression level of VEGF and the uptake of 18F-FDG in 32 cases whose expression of VEGF were positive was studied to evaluate the inner relationship on the molecular level. The results showed that the VEGF and the MVD value carried no relation with the type of lung cancer (P>0.05). The VEGF and the MVD value were related to the lesion's size and lobulation sign, spinous protuberance, pleural retraction sign, and vessel convergence sign (P<0.05), though it showed no relation to spiculation sign (P>0.05). The relationship between the expression level of VEGF and the uptake of 18F-FDG in 32 cases whose expression of VEGF were positive was evaluated.The result showed that the expression of VEGF and SUV had positive correlations (r=0.355, P<0.01); the expression level of VEGF was changed with SUV in the same direction .The SUV of tumor focus and the expression of VEGF of NSCLC tumor tissues were changed in the same direction. We could draw a conclusion that the SUV of tumor focus perhaps reflected the correlated information about the tumor angiogenesis indirectly, which means we could get more important index about the growth types, speed, metastasis and prognosis of NSCLC . The result suggested that we could provide much more evidences about diagnosis, therapy and prognosis of NSCLC for clinic.