Expression Of Endocan And VEGF In Human Glioblastoma

Background: Glioma is a common malignant tumor of the brain,of which the most malignance is Glioblastoma(GBM)(WHO grade IV).The latest Central Nervous System Tumor Classification(2016 WHO)introduced molecular pathology,which reclassifies gliomas into different subtypes based on IDH mutations and 1p / 19 q codeletions.Then,glioblastoma is divided into two subtypes—IDH mutant and IDH wildtype.The histopathological features of glioblastoma are including invasive growth,nuclear atypia,high proliferation index,necrotic foci,microvascular proliferation,and polymorphic vascular structures.The morphology,function,and molecule of microvascular proliferating and highly abnormal vascular structures in glioblastoma are significantly different from normal cerebral vessels.The microvascular density(MVD)of glioblastoma is associated with tumor grade and is an independent indicator of poor prognosis in patients.A variety of pro-angiogenic factors are expressed in highgrade glioblastoma and promote angiogenesis,the most important of which is vascular endothelial growth factor(VEGF).In recent years,Endocan has been found as a marker of tumor angiogenesis,which helps to reveal the invasiveness and recurrence of tumors.The expression of Endocan in glioblastoma has been reported,but the relationship of glioblastoma subtypes(IDH mutant and IDH wild)is still unclear.The treatment of glioblastomas are personalized and usually involves operation,radiotherapy,and chemotherapy.Despite comprehensive treatment,the median survival of patients with glioblastoma is still unsatisfactory.Anti-angiogenic targeted therapies for glioblastoma may be a new treatment option.Objective:Detecting the expression of Endocan,VEGF and MVD in glioblastoma pathological tissues by immunohistochemistry and the expression of Endocan m RNA in glioblastoma tissue samples by reverse transcription-polymerase chain reaction(RTPCR).To analyze the expression levels of Endocan,VEGF,and MVD in glioblastoma tissues,and to explore the correlation between the expression of which in each subtype of glioblastoma(IDH mutant and IDH wild).Supporting for the diagnosis and antivascular targeted therapy of glioblastoma.Method:74 cases of glioblastoma specimens(32 cases in IDH mutant group,42 casesin IDH wild group)and 20 normal brain tissue samples(control)were collected.Tissue microarrays were prepared from representative regions of tumor tissues and immunohistochemical staining of Endocan,VEGF and MVD were performed.30 cases of fresh glioblastoma specimens(15 in IDH mutant group,15 in IDH wild group)were collected,and the expression level of Endocan m RNA was detected by RT-PCR.Statistical analysis was performed by software IBM SPSS Statistics 25(SPSS,Chicago,IL).The expression differences and correlations of Endocan,VEGF,MVD,and Ki-67 between different subtypes of glioblastoma(IDH mutant and IDH wild)were compared.Result:1.Immunohistochemistry results showed that Endocan is not expressed in glial cells and blood vessels in normal brain tissues,while Endocan protein is expressed in cytoplasm and blood vessels in glioblastoma tissues.Normal brain tissue has no VEGF protein expression,while VEGF protein has expressed in glioblastoma.The expression of Endocan and VEGF were different in the IDH wild type group and IDH mutant group(P<0.05),and the IDH wild type group was higher than the IDH mutant group.2.The results of immunohistochemistry showed that the CD34 expression of MVD is localized to the cell membrane.The CD34-positive microvascular in normal brain tissue are rarely and equally distributed,and the structure of small lumen is basically the same;However,in glioblastoma,the density of microvascular is increased and the distribution is uneven,the morphology and size of the lumen are different.The expression of MVD was different in the IDH wild type group and the IDH mutant group(P<0.05),and the IDH wild type group was higher than the IDH mutant group.There was no significantly different in glioblastoma IDH wild type and IDH mutant at the expression of Ki-67,which is localized in the nucleus.3.RT-PCR analysis showed that the expression of Endocan m RNA in the glioblastoma IDH wild type group was higher than that in the IDH mutant group(P<0.05).4.Correlation analysis showed that the expression of Endocan and VEGF in glioblastoma was positively correlated with MVD(r=0.54,r=0.65,P<0.01);the expression of Endocan and VEGF was positively correlated with Ki-67(r=0.48,r=0.54,P < 0.01).Conclusion: Endocan is highly expressed in glioblastoma.Compared with IDH mutant glioblastoma,the expression of Endocan and VEGF in IDH wild-type glioblastoma is significantly enhanced.Endocan can be used as a marker of neovascularization in glioblastoma to reflect the malignancy of tumors and even predict the prognosis of patients.