Expressions Of Nanog And Dpagt1 In Breast Cancer And Their Clinical Significances

Objective: Breast cancer is the most common malignancy in women;currently,115 million patients have breast cancer,resulting in 410,000 deaths annually worldwide.Although current anti-tumor therapies have greatly improved the 5-year survival rate of breast cancer patients,recurrence and long-distance metastasis of breast cancer after surgical resection of the primary tumor are often incurable and are the leading causes of mortality in breast cancer patients.Therefore,it is always a big challenge for medical researchers to look for new therapy which could effectively inhibit the invasion and metastasis of tumor.Nanog is a transcription factor that is involved in the self renewal of embryonic stem cells(ES).Years of investigations revealed that the Nanog gene and its isoforms play an important role in the development of a malignant phenotype in cells.The transcription factor Nanog is expressed in many malignant human tumors,including ovarian cancer,and bladder cancers,gastric adenocarcinoma,melanoma and many others.In research about nasopharyngeal carcinoma(NPC),Nanog expression is inversely correlated with high expression of E-cadherin and positively correlated with high expression of N-cadherin.Expression of Nanog in NPC can promote tumor cell growth,anti-apoptosis properties and metastasis.It was shown that the excessive proliferation,migration and invasion of ovarian cancer cells with Nanog expression are related to the regulation of E-cadherin.Knock-down of Nanog results in a decreased metastatic potential of ovarian cancer cells and an increase in E-cadherin m RNA levels.Conversely,Nanog overexpression leads to enhanced cell proliferation and migration and decreased E-cadherin m RNA levels.These data demonstrate that Nanog is specifically involved in the process of carcinogenesis and can be a potential biological and prognosticmarker for malignant tumors.Dpagt1(UDP-Glc NAc-dolichol-phosphate N-acetylglucosamine-1 phosphate transferase)encoded the first and rate-limiting enzyme in the assembly of the lipid-linked oligosaccharide precursor in the endoplasmic reticulum and thus mediated N-glycosylation of many proteins.Overexpression of Dpagt1 drived cell proliferation,altered cell surface properties and led to immature adherens junctions.Downregulation of Dpagt1 results in mature adherens junctions forming and thus inhibits cell proliferation.In humans,mutations in Dpagt1 result in a significant reduction in GPT activity,giving rise to congenital disorders of glycosylation(CDG-Ij)and early mortality.While depletion of Dpagt1 results in severe disorders,including hypoglycemia,hypoxemia,hypokinesia and mental retardation,its overexpression is linked to oral squamous cell carcinoma(OSCC)tumorigenesis However,the relationship of Nanog and Dpagt1 in breast cancer formation and development has not been reported.Therefore,this study was to explore Nanog and Dpagt1 expression in breast cancer and their relationship with clinical pathological characteristics of breast cancer.Methods:1 Samples collection: In this study,there are 100 cases of paraffinembedded breast cancer tissue specimens were randomly selected,30 cases corresponding adjacent normal breast tissues(normal breast tissue carcinoma distance within 2cm)as the control group.All cases are from Pathology Department of Xingtai City People's Hospital during January 2012 to January2014.2 Experimental methods: The samples were fixed by 10% formal-dehyde,embeded in paraffin after excision.Method of immunohistochemistry staining was used to detect the expression of Nanog and Dpagt1 proteins in 100 cases of breast cancer tissues and 30 cases of normal breast tissues.Evaluation of immunohistochemistry staining: The positive reaction of Nanog and Dpagt1 were identified in nuclear and cytoplasmic matrix,characterized by brown-yellowish granules.The number and staining intensityof the positive cells were synthetical scored and the half-quantitative analysis was assessed by the score above mentioned.Statistical analysis: The categorical data was assessed by Chi-square analysis.Spearsman correlation analysis was used to assess the correlation between different variables.The statistical significance was set to 0.05.Results:Results:1 Expressions of Nanog in breast cancer and their clinical significances1.1 Expression of Nanog in breast cancer and the normal tissueThe positive reaction of Nanog was identified in nuclear and cytoplasmic matrix,characterized by brown-yellowish granules.The positive expression rate of Nanog protein in breast cancer was 48%(48/100).The Nanog protein did not express In normal tissue(0/30).The expression of Nanog in breast cancer was significantly higher than that of normal tissue(?2=22.829,P<0.01).1.2 Expression of Nanog in breast cancer and its clinical significancesCorrelations between Nanog expression and clinicopathological features are listed in Table1.As shown in Table1,age and menpause were not associated with positive expression of Nanog in breast cancer as determined by correlation analysis(P>0.05).However,there were positive correlation between lymphatic metastasis and expression of Nanog in breast cancer patients(P<0.01),which meant Nanog expression was much higher in breast cancer patient with lymphatic metastasis than those patient without metastasis.Similarly,there were positive correlational relationship between TNM stage,tumor pathological stage and Nanog expression(P<0.05,P<0.05).Correlations between Nanog expression and ER,PR,C-erbB-2 expressions in breast cancer are listed in Table2.As shown in Table2,there were negative correlation between Nanog expression and ER expression in breast cancer(r=-0.238,P<0.05).The expression of Nanog was negatively related with PR expression(r=-0.239,P<0.05).Similarly,there were negative correlation between Nanog expression and C-erb B-2 expression in breast cancer(r=-0.217,P<0.05).It meant that expression of Nanog in ER,PR,C-erb B-2 negative breast cancer patients was much higher than that in those ER,PR,C-erbB-2 positive breast cancer patients The expression of Nanog was positive related with ki-67 expression(r=0.257,P<0.05).2 Expressions of Dpagt1 in breast cancer and their clinical significances2.1 Expression of Dpagt1 in breast cancer and the normal tissue The positive reaction of Dpagt1 was identified mainly in cytoplasmic matrix,characterized by brown-yellowish granules.The positive expression rate of Dpagt1 protein in breast cancer was 68%(68/100).The positive expression rate of Dpagt1 protein in normal tissue was 20%(6/30).The expression of Dpagt1 in breast cancer was significantly higher than that of normal tissue(?2=21.683,P<0.01).2.2 Expression of Dpagt1 in breast cancer and its clinical significances Correlations between Dpagt1 expression and clinicopathological features are listed in Table1.As shown in Table3,age and menpause were not associated with positive expression of Dpagt1 in breast cancer as determined by correlation analysis(P>0.05).However,there were positive correlation between lymphatic metastasis and expression of Dpagt1 in breast cancer patients(P<0.05),which meant Dpagt1 expression was much higher in breast cancer patient with lymphatic metastasis than that in those patients without lymphatic metastasis.Similarly,there were positive relationship between TNM stage,tumor pathological stage and Dpagt1 expression(P<0.05,P<0.05).Correlations between Dpagt1 expression and ER,PR,C-erbB-2 and ki-67 expressions in breast cancer are listed in Table 4.As shown in Table4,there were no correlation between Dpagt1 expression and ER expression in breast cancer(P>0.05).Similarly,expression of Dpagt1 was not significantly associated with PR expression in breast cancer(P>0.05).However,there were positive correlation between Dpagt1 expression and C-erb B-2 expression in breast cancer(r=0.241,P<0.05).The expression of Dpagt1 was positively correlated with ki-67 expression(r=0.233,P<0.05).It meant that expression of Dpagt1 in C-erb B-2 or ki-67 positive breast cancer patients was much higher than that in those ER,PR,C-erb B-2 negative breast cancer patients3 Correlation between Nanog and Dpagt1 expressions in breast cancer As determined by Spearman correlation analysis,there was a positive relationship between Nanog expression and Dpagt1 expression in breast cancer(r=0.316,?2=9.974,P<0.05)(Table 5).It was shown that Nanog protein and Dpagt1 protein were highly expressed in breast cancer,which may be associated with the development of cancer and play a key role in the invasion,metastasis and prognosis.Conclusion:1 The Nanog protein did not express in the normal epithelial of breast tissue,but it highly expressed in breast cancer.The expression of Nanog protein in breast cancer was intensively associated with several known prognostic indicator including ER,PR,ki-67 index,pathological stage,tumor TNM stage and lymphatic metastasis.These findings revealed that the Nanog protein could promote cancer cells proliferation,migration and inhibit cell differentiation.Therefore Nanog could be a potential biological and prognostic marker for breast cancer.2 The Dpagt1 protein expressed low level in normal breast epithelial and high level in breast cancer.The expression of Dpagt1 protein in breast cancer was intensively associated with several known prognostic indicator such as ki-67 index,pathological stage,tumor TNM stage and lymphatic metastasis,while Dpagt1 expression had no correlation with ER,PR expression.These findings demonstrated that Dpagt1 mignt be involved in the process of carcinogenesis and development of breast cancer and it was closely related with proliferation potency of cancer cells.3 There was a positive correlation between the expressions of Nanog and Dpagt1 in breast cancer,which indicated that the two genes may cooperate and promote carcinogenesis and development of breast cancer and play an important role in the invasion,metastasis,and prognosis of breast cancer cells.