Expression Of PTPN9 In Pancreatic Cancer And Clinical Significance

Background : Pancreatic cancer is one of the most deadly tumors with poor prognosis in the world,and its incidence rate is increasingly growing every year.Due to the concealed location of pancreas,the hidden clinical symptoms,also the lacks of sensitive and accurate examination methods,it is difficult to be diagnosed in the early stage of the disease.To date,Radical resection is the most effective way to improve the prognosis of pancreatic cancer patients.But most patients turned out to be found in the middle or late stage or have already transferred when they looked for help,thus they lost their best time for the treatment.Therefore,it is important and urgent to study the etiology and pathogenesis of pancreatic cancer and to provide a theoretical basis for the diagnosis and treatment of pancreatic cancer.Protein tyrosine phosphatase non-receptor type 9(PTPN9,also known as PTPMEG2)is a member of the protein tyrosine phosphatases(PTPs).It is known that PTPs family is an important regulator in cell signal transduction,negatively regulates a variety of biological signal pathways,participates in cell proliferation,differentiation,adhesion and metastasis,and play an important and different role in the occurrence,development and metastasis of cancers.Signal transduction and activator of transcription 3(STAT3)is a kind of signal transduction and transcriptional activators which can be frequently activated in pancreatic cancer in the form of phosphorylated STAT3(p-STAT3)and can be involved in the proliferation and invasion of pancreatic cancer.PTPN9 can inhibit STAT3 related signaling pathway through direct and indirect ways.However,few studies have been down on the relationship between PTPN9 and pancreatic cancer.In this study,the expression level of PTPN9 in clinical samples of pancreatic cancer is to be detected.Also,the relationship between PTPN 9 and clinical pathological data and p-STAT3 is to be analyzed.Objective: To detect the expression level of PTPN9 and p-STAT3 in the clinical samples of pancreatic cancer,and try to explore the relationship between the expression level of PTPN9 and clinicopathological features and the expression level of p-STAT3.Methods: Cancer tissues and corresponding paracancerous tissues of pancreatic cancer patients were collected,and the expression of PTPN9 and p-STAT3 in samples was detected by qRT-PCR,Western-Blot and immunohistochemistry from mRNA levels and protein levels.The correlation between the expression of PTPN9 and clinical pathological parameters of patients and the expression of PTPN9 was statistically analyzed.Results: qRT-PCR and Western-Blot results showed that the expression level of PTPN9 in pancreatic cancer tissues was lower than its adjacent tissues(P<0.01),and the difference was statistically significant.The results of immunohistochemistry showed that the expression level of PTPN9 in pancreatic cancer tissues was lower and p-STAT3 is highly expressed in pancreatic cancer tissues,and the expression level of PTPN9 is negatively correlated with p-STAT3.In the correlation analysis between the results of immunohistochemistry and clinical pathological parameters,we found that the expression level of PTPN9 was related to the vascular invasion and lymph node metastasis.The lower the low level of PTPN9,the more prone to vascular invasion and lymph node metastasis.Conclusion: The expression level of PTPN9 is significantly downregulated in pancreatic cancer and negatively correlated with the activation of STAT3 expression,vascular invasion and lymph node metastasis of the pancreatic cancer patients.It is suggested that PTPN9 may be used as a detection biomarker to evaluate tumors' development and prognosis.