Significance And Expression Of Angiopoietin-like Protein 5 In Human Primary Gastric Cancer Tissues

[Background]Gastric cancer(GC)is one of the most common malignancies all over the world.Although the incidence of gastric cancer is declined in recent years,the mortality rate remains the second leading cause of cancer-related death in the world.And GC is particularly prevalent in China.The characteristics of both high morbidity and mortality could be mainly attributed to the aggressive course of GC.At present,the efficacy of available systemic treatment strategies still limited because of asymptomatic manifestations.Hence it is significant to explore the mechanism of GC development and to study the novel and efficient target for this disease.Angiopoietin-like protein 5(ANGPTL5),which is mainly expressed in adult human heart tissues,regulates the lipoprotein metabolism and supports the efficient expansion of HSCs without compromising their repopulating potential.Recently,some studies discovered that ANGPTL5 is expressed in acute myelocytic leukemia(AML)cells and non-small-cell lung cancer(NSCLC)cells,which is associated with tumor cell differentiation,however,the role of ANGPTL5 in GC has not yet been explored.So,we detected the expression of ANGPTL5 in human GC tissues and further analysed the association between ANGPTL5 expression and the prognosis factors GC patients.Taken together,not only has this study attempted to demonstrate the significance of ANGPTL5 in GC,but also highlights the potential target in anticancer treatment of GC.[Objective]To detect the expression of ANGPTL5 in human GC tissues.And then we try to analyze the different expression of ANGPTL5 between GC tissues and paired adjacent normal tissues.In addition,we attempt to analyze the correlation between ANGPTL5 expression and prognosis factors including clinicopathological parameters,MVD and OS.[Methods]1.73 human primary GC specimens,including cancer tissues and paired adjacent normal tissues,were obtained patients who underwent gastrectomy for GC in Jinan Central Hospital Affiliated to Shandong University(Shandong,China)from 2009.12 to 2011.8.IHC were used to detect the expression of ANGPTL5 in cancer tissues and paired adjacent normal tissues.And then CD34 was also detected by IHC in GC tissues.2.Chi-square test were used to analyze the difference of ANGPTL5 expression between gastric cancer tissues and adjacent normal tissues.The association between clinical pathological parameters and ANGPTL5 expression in GC tissues were analyzed by Pearson Chi-square test or continuity correction for Pearson Chi-square test.Then the correlation between ANGPTL5 and MVD in GC was analyzed by Spearman correlation test.Finally,to predict the influences of ANGPTL5 expression on GC patients'prognosis,the overall survival time were defined from the surgery date to the date of death or the last day of the follow-up evaluation,and survival curves were drawn using the Kaplan-Meier method and compared with Log-rank test.[Results]1.ANGPTL5 protein was mainly expressed in GC cells,presented pale yellow or brown in cytoplasm,but faint staining in small parts of membrane or nuclear of GC cells.ANGPTL5 protein was little expressed interstitial cell.In adjacent normal tissues,there were diffused faint staining in cytoplasm of some gastric mucosa cells.2.ANGPTL5 protein expression in GC tissues(48/73)was higher than the expression in adjacent normal tissues(11/73)(?2=38.939,P<0.001).3.ANGPTL5 expression was significantly correlated with primary tumor size(?2=5.006,P=0.025),depth of tumor infiltration(?2=6.810,P=0.009)and clinical stages(?2=4.867,P=0.027).However,there was no significant associations between ANGPTL5 protein expression and patients' age,gender,cellular differentiation or regional lymph node involvement(P>0.05).4.The expression of ANGPTL5 was positive correlated with MVD in human primary human GC tissues(R=0.480,P<0.001).5.ANGPTL5 protein expression was associated with OS of GC.The OS of ANGPTL5-positive group is obviously lower than ANGPTL5-negative group(?2=5.888,P=0.015).[Conclusions]Our study suggested that ANGPTL5 was expressed highly in GC tissues and was associated with primary tumor size,tumor infiltration,TNM stages and OS.ANGPTL5 was also positive correlated with MVD.It indicated that ANGPTL5 might be one of the factors participated in GC progression by involving in tumor angiogenesis.Therefore,it is a potential prognostic marker and therapeutic target for GC patients.