The Expression And Clinical Significance Of EGFL7 And E-cad In Cervical Cancer Tissues

Background and Objective:Most of the direct causes of death in patients with malignant tumors are Multiple organ dysfunction syndrome（MODS）.The underlying cause is a series of pathological changes caused by multiple metastases of tumors.It has been pointed out that although many tumor cells have significant differences in histological characteristics,their process of local infiltration and distant metastasis is basically consistent^[1].Epidermal growth factor-like-domain mutiple-7（EGFL7）is a factor specifically expressed in endothelial cells.Its main function is to promote the formation of vascular lumen and maintain the normal physiological functions of vascular endothelial cells,but it can also affect the formation and morphological construction of blood vessels under pathological conditions^[1,2].Microvessel density is one of the quantitative indicators of angiogenic activity or intensity,of which CD34was identified as a marker of pan-vascular endothelial cells and was not specific to tumor microvessels.EMT refers to a special kind of cell transformation phenomenon.When the body is in a specific physiological state or pathological state,epithelial cells will be transformed into mesenchymal cells under the stimulation and induction of various factors,so as to obtain certain migration ability.The reduction of cell surface adhesion molecules during EMT leads to a decrease in adhesion,but the migration ability is significantly enhanced,and the expression of epithelial cadherin（E-cad）is down-regulated or silenced,and this protein is an epithelial cell-specific marker.The clinical incidence of cervical cancer is high.After research for years,the disease may be the only preventable malignant tumor.However,the occurrence and development process of cervical cancer is very complicated.The common clinical pathogenic factor that has been confirmed is high-risk HPV virus infection.A large number of studies have shown that neovascularization and epithelial-mesenchymal transition are closely related to cervical cancer progression.This experiment is based on the detection and analysis of EGFL7,E-cad expression and microvessel density in different cervical tissues,to further explore their roles in the pathogenesis of cervical cancer and their mutual relations,and gradually enrich the diagnosis and treatment of cervical cancer.Methods:1.Collected 80cases of hospitalized patients at the Gynecology and Obstetrics of the Affiliated Hospital of Southwest Medical University from 10/2016 to10/2017.Through pathological diagnosis,38 cases belongs to cervical cancer,23 cases belongs to cervical intraepithelial neoplasia,and 19 cases belongs to normal cervical tissue.The pathological specimens of patients were then paraffin-embedded and sectioned,HE stained and immunohistochemical stained.2.Adopted the Envision Method to detect the expression of EGFL7,E-cad and CD34 in each pathological specimen.3.Used the Chi-Square Test for the data calculating,Fisher’s Exact Probability Method for the significance analysis,and the Spearman Analysis Method for the multi-factor correlation analysis.P<0.05indicated that the data comparison was statistically significant.Results:1.The EGFL7 protein was highly expressed in vascular endothelial cells and tumor epithelial cells,and after staining,brownish yellow particles scattered in the cytoplasm.The positive expression rates of EGFL7protein in normal group,CIN and cervical cancer were 10.53%（2/19）,43.48%（10/23）and 68.42%（26/38）respectively.The expression of EGFL7 was positively correlated with the degree of cervical cancer.Comparative analysis showed that there was a statistical difference between the three groups of data（χ²=18.786,P<0.001）.The data of the three groups of patients were compared in pairs,and the results showed that the data comparison between two groups all was statistically significant（P≤0.001）.2.The expression of EGFL7 in cervical cancer tissues was not related to the age of patients,the histopathological type of cancerous tissue,the degree of differentiation of cancer cells,the degree of invasion and metastasis,and the expression of EGFL7 was not statistically different（P>0.05）.3.The positive staining of E-cad protein was mainly located in the cell membrane and cytoplasm,which was shown as sepia particles.The positive expression rates of E-cad protein in normal group,CIN group and cervical cancer group were 94.74%（18/19）,65.22%（15/23）,and 28.95%（11/38）respectively.There was a negative correlation between the expression level of E-cad and the severity of cervical lesions,and there was statistical difference between the three groups（χ²=23.513,P<0.001）.The data of the three groups were compared in pairs.The results showed that the data comparison between two groups all was statistically significant（P≤0.001）.4.The expression of E-cad in cervical cancer tissues was not related to the patient’s age,pathological type of cancerous tissue,differentiation of cancer cells,infiltration and metastasis（P>0.05）,but related to FIGO stage and lymph node metastasis（P<0.05）.5.The positive staining of CD34 protein was mainly located in the cytoplasm,the microvascular endothelial cells or endothelial cell clusters,which was shown as brownish yellow particles.Then the single endothelial cells or endothelial cell clusters stained by CD34 were regarded as a blood vessel marker to detect the microvessel density in tissues.The Weidner Method will be referred to for the calculating of the microvessel density.The detection values of microvessel density in the normal group,CIN group,and cervical cancer group were 23.85±8.371,35.007±6.117,and 67.625±10.767 respectively.There was a statistically significant difference among the three groups（P<0.001）.The data comparison between two groups all was statistically significant（P<0.017）.6.In the cervical cancer group,the expression of MVD was not related to the age of the patients（P>0.05）,but it was closely related to the FIGO stage,tumor type,local infiltration characteristics,distant metastasis characteristics（P<0.05）.7.Expression of EGFL7 and E-cad was negatively correlated in cervical cancer tissues（r_s=-0.815,P<0.001）.8.Among the 38 cases of cervical cancer,26patients with EGFL7 positive expression and 12 patients with EGFL7negative expression had mean microvessel density of 71.9718±8.8485and 55.4992±4.5979 respectively.There was a significant difference between the two groups（P<0.001）.Analysis with Pearson revealed obviously positive correlation between EGFL7 and MVD expression（r_s=0.238,P<0.05）,indicating the increase of EGFL7 expression would result in an increase of MVD value.9.In the 38 cases of cervical cancer,11 patients with E-cad positive expression and 27 patients with E-cad negative expression had mean microvessel density of 56.5407±6.3878and 71.2242±9.3531 respectively.There was significant difference between them（p<0.001）.Analysis with Pearson revealed that E-cad was obviously negatively correlated with MVD（r_s=-0.339,P<0.05）,suggesting the increase of E-cad expression would result in a large decrease of MVD value.Conclusions:1.EGFL7 expression can be found in the cytoplasm of normal cervix,CIN and cervical cancer tissues.EGFL7 was expressed at low level or silenced in normal cervical tissues,but it was highly expressed in cervical cancer tissues.Plus,the increasing severity of cervical lesions indicated that EGFL7 may be involved in the development of cervical cancer.2.E-cad expression can be found in the cell membrane and cytoplasm of normal cervix,CIN and cervix cancer tissues,and decreased with the severity of cervical lesions.E-cad protein plays an important role in restraining the progression of cervical cancer.The role as a key factor of EMT,at the same time,further reflects the close relationship between cervical cancer and EMT.3.MVD showed an upward trend with the aggravation of cervical lesions,further confirming that cervical cancer,as a solid tumor,depends on microvascular to grow and metastasize.New blood vessels promote the occurrence and development of cervical cancer.4.There is a positive correlation between EGFL7 and MVD value in cervical cancer tissues.It is further verified that EGFL7 plays an important role in the promotion of angiogenesis and luminal formation.Therefore,EGFL7 can be used as a new target for tumor therapy to block the tumor blood supply and delay the tumor progresses.5.There is a negative correlation between EGFL7 and E-cad in cervical cancer tissues.The down-regulation or absence of E-cad is the most important key marker of EMT.Based on this,it is presumed that EGFL7 may promote the occurrence and development of cervical cancer through epithelial-mesenchymal transition.6.There is a negative correlation between E-cad and MVD value in cervical cancer tissues,indicating that with the process of cervical epithelial-mesenchymal transition,MVD value increased.Tumor neovascularization provides the necessary microenvironment for EMT process,which further promotes the occurrence and development of cervical cancer.