Midkine promotes perineural invasion in human pancreatic cancer

AIM:To investigate midkine(MK)and syndecan-3protein expression in pancreatic cancer by immunohistochemistry,and to analyze their correlation with clinicopathological features,perineural invasion,and prognosis.METHODS:Pancreatic cancer tissues(including adequately sized tumor tissue samples and tissue samples taken from areas less than 2.0 cm around the tumor)were taken from 42 patients who were undergoing a partial duodenopancreatectomy.MK and syndecan-3proteins were detected by immunohistochemistry using a standardized streptavidin-peroxidase method,and analyzed for their correlation with clinicopathological features,perineural invasion,and prognosis.Associations of neural invasion with aggressive characteristics of pancreatic cancer and the presence of perineural invasion were assessed by two independent observers blinded to the patient status.RESULTS:MK and syndecan-3 were found in 26(61.9%)and 24(57.1%)specimens,respectively.MK and syndecan-3 expression was associated with perineural invasion(P=0.018 and 0.031,respectively).High MK expression was closely associated with advanced tumor,node and metastasis stage(P=0.008),lymph node metastasis(P=0.042),and decreased postoperative survival at 3years(51.0%vs 21.8%,P=0.001).Syndecan-3 levels were correlated with tumor size(P=0.028).Patients who were syndecan-3 negative had a higher cumulative survival rate than those who were positive,but the difference was not significant(44.0%vs 23.0%,P>0.05).CONCLUSION:MK and syndecan-3 are frequently expressed in pancreatic cancer and associated with perineural invasion.High expression of MK and syndecan-3may contribute to the highly perineural invasion and poor prognosis of human pancreatic cancer.