Aberrant Expression And Prognostic Value Of RacGAP1 Protein In Hepatocellular Carcinoma

Backgroud: Primary liver cancer,whose the most common pathological type is hepatocellular carcinoma(HCC),is one of the most common malignancies in the world.Every year the growing number of new cases of HCC in the world is 748 thousand.Tumor-related mortality ranks the third place,besides,the fact is that HCC's morbidity and mortality in China are the highest in the world.Owing to insidious onset,it is difficult to early diagnose HCC.When most cases were diagnosed,they have been at an advanced stage,so they lose the opportunities of radical resection.Moreover,after surgery,patients usually have symptoms of recurrence and metastasis,and high recurrence rate is also the main reason for the survival of patients with liver cancer.Currently,AFP,tumor size,vascular invasion,pathological grade,and so on,have been used as prognostic indicators of liver cancer,but the literature is agreed that there is a lack of proven prognostic molecular markers of liver cancer.Therefore,it is of great significance to actively search for valuable molecular markers for early diagnosis and prognosis of HCC.RhoGTP1 is a kind of activator protein that conservatively acts on the GTP of RhoGTP enzyme family,which belongs to the GTP enzyme activator family.RACGAP1 has been shown to be highly expressed in a variety of malignant tumor cells,and its high expression in a great number of malignant tumors has been proved to be associated with a variety of clinical parameters and poor prognosis.However,there are few reports about the relationship between RACGAP1 expression and prognosis in HCC among the current literature.?Objectives?The research was conducted to detect the expression level of RACGAP1 protein in HCC,and analyze its relationship with clinicopathological parameters of HCC,and investigate the role of RACGAP1 protein in HCC development and its prognostic value.?Methods?(1)In this study,the clinical information and pathological specimens of HCC patients who have been surgically resected in the First Affiliated Hospital of Bengbu Medical College during the period from 2008(January)to 2012(December)were collected.Among all cases,93 had complete medical records and pathological grade,78 of which had follow-up surveys.All outpatient information,hospital review information and telephone follow-up information were recorded in the patients' case reports.30 cases of hepatic puncture specimens were collected and 39 cases of cirrhosis puncture specimens were collected.18 cases of normal liver specimens collected from adults with traumatic hepatectomy or accidental death were used as normal controls.(2)The expression and localization of RACGAP1 protein in 93 cases of HCC,39 cases of liver cirrhosis,30 cases of hepatitis and 18 cases of normal liver tissue were detected by immunohistochemistry.(3)The differential expression of RACGAP1 protein in 10 pairs of fresh frozen liver cancer tissues and 10 cases of fresh normal liver was detected by Western blot.(4)The relationship between RACGAP1 protein and the clinicopathological parameters was analyzed,and its influence in the prognosis of HCC was investigated.(5)Statistical Methods: All clinical data were entered into Microsoft Excel 2007(Microsoft;Redmond,WA,USA),and all statistical analyses were performed using the statistical software SPSS version 17.0(SPSS,Inc.;Chicago,IL,USA).Differences of proportions were tested for statistical significance with chi-square test or Fisher's exact text,and the overall survival was estimated by Kaplan-Meier method.The correlation between RACGAP1 expression and clinic-pathological features of HCC patients were evaluated by using chi-square test,while the associations of RACGAP1 expression and clinic-pathological features with the clinical prognosis were examined with KaplanMeier method and log-rank test.Factors affecting the overall survival of HCC patients were identified by using Cox regression analysis.A P value < 0.05 was considered statistically significant.?Results?(1)Immunohistochemical staining revealed negative RACGAP1 expression in normal liver specimens,and liver biopsy specimens of hepatitis and hepatic cirrhosis patients,while 44.1%(41/93)of HCC specimens were positive for RACGAP1(P < 0.05).In the HCC specimens,RACGAP1 was predominantly expressed in the cytoplasm,and partially co-localized in the nucleus and cytoplasm.(2)The expression of RACGAP1 protein in 10 pairs of fresh frozen liver cancer tissues and 10 cases of fresh normal liver was detected by Western Blot.The results showed that the expression level of RACGAP1 protein in 3 pairs of HCC specimens was significantly higher than that in normal liver tissues.(3)The RACGAP1 expression was found to correlate with the tumor size,pathological grading,TNM stage,vascular tumor thrombus and lymph node metastasis of HCC(all P values < 0.05),but not with patients' gender or age(both P values > 0.05).Univariate analysis showed a significantly lower survival rate in HCC patients with positive RACGAP1 expression,vascular invasion and advanced TNM stage,while multivariate analysis revealed that high RACGAP1 expression was an independent prognostic factor in HCC patients.?Conclusion?The results of this study demonstrate aberrant expression and abnormal localization of RACGAP1 in cytoplasm and nucleus,demonstrate that its high expression is associated with many clinicopathological parameters and prognosis,and suggest that it plays an important role in the development and progression of HCC.RACGAP1 may have a promising value to serve as a biomarker for malignant biological behaviors and poor prognosis of HCC.