| Background and purpose: Renal cell carcinoma (RCC) is the most common malignancy of the kidneys. The use of Spiral CT (SCT) has proved to be an effective method in early diagnosis, treatment as well as predicting prognosis of RCC. Angiogenesis plays an important role to the growth and metastasis of the tumor. The microvessel density (MVD) is now widely used to evaluate the tumor angiogenesis, and has been proved to correlated with the tumor infiltration and prognosis. Tumor angiogenesis is controlled by a number of angiogenic factors, among which vascular endothelial growth factor (VEGF) plays an important role in neovascularization, and has been proved to be related to aggressiveness and prognosis of many solid tumors. Proliferating cell nuclear antigen (PCNA) is an auxiliary protein of DNA polymerase-8 and has been found only in the nuclei of proliferating cells in the late GI5and the S phase. All imaging features are based on its pathological nature and determined by biological behaviors, so that a comparison between SCT features and its biologic behaviors may devote to the relationship between modern medical imaging and molecular biology. The purpose of this study was to evaluate the correlation between SCT features and pathology, MVD, expressions of VEGF and PCNA in renal cell carcinoma.Materials and methods: MVD, expressions of VEGF and PCNA in 34 patients with RCC diagnosed by pathology were examined immunohistochemically using SABC techniques. Spiral CT examinations were performed with a GE Hispeed advantage Rp22 helical scanner. After unenhanced helical CT scans were performed, contrast medium (Omnipaque or Ultravist 300mg.I/ml) was injected intravenously with a power injector at a rate of 3.5ml/s. The volume of contrast medium was 90-100ml (1.5ml/kg weight). Two-phase enhanced helical CT scans were obtained at 30s (corticomedullary phase CMP) and 80s (nephrographic phase NP) respectively after the beginning of injection. The scan parameters were HOKVp, 260-280mAs, collimation 5-7mm, pitch = 1. The SCT and pathological staging of RCC were performed using Robson classification. The relationship between SCT features and pathology, MVD, expressions of VEGF and PCNA wasanalyzed thoroughly. Statistical analysis was executed by SPSS 10.0 software. The enumeration data of the groups were compared using t-test, the binary data were compared using Fisher's exact test, significant level a = 0.05.Results: (1) The detection and characterization rate as well as accuracy of staging of 34 renal cell carcinomas of two-phase enhanced SCT scans were 100%, 100% and 94%, respectively. Tumors with clear margin on SCT scans were closely correlated with pseudocapsules at pathological examination (p<0.01). The nuclear grade was higher in groups of tumor having blurred margin, central necrosis than in those of tumor having clear margin, without central necrosis (p<0.01, p<0.01, respectively). (2) In 34 cases of RCC, the mean MVD was 89.5 ?6. The positive expression rate of VEGF and PCNA were 70.6% (24/34), 58.8% (20/34), respectively. At pathologic evaluation, all MVD, positive expressions of VEGF and PCNA were obviously higher in groups of tumor having poorly pseudocapsule, high nuclear grade, central necrosis and bleeding than in those of tumor pseudocapsulated, having low nuclear grade, without central necrosis (p<0.05 respectively in each of the groups). MVD was higher in tumors with intravenous tumor emboli than in tumors without emboli (pO.Ol). PCNA positive expression and nuclear grade were higher in tumors with the diameter larger than 3.0cm than in those with diameter less than 3.0cm. MVD,7expressions of VEGF and PCNA were closely correlated with Robson staging. (3) The MVD, positive expressions of VEGF and PCNA in groups of tumor having blurred margin, central necrosis on SCT scans were higher than in those tumor having clear margin, without central necrosis (p<0.05 respectively in each of the groups). On CMP scans, MVD was closely correlated with tumor enhancement (p<0.05).Conclus...
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