Expression Of Brain-derived Neurotrophic Factor In Pancreatic Duct Cancer And Its Clinical Significance

【Abstract】Pancreatic ductal adenocarcinoma (PDAC) is the most common pancreaticcancer, which has an insidious onset. Being a high-grade malignant tumor, PDAC hasshown an increasing trend in morbidity across the world. With a significant rise in theoccurrence rate (about3to7times during the past30years), pancreatic cancer is thefifth deadliest cancer[1].In china, the morbidity rate of pancreatic cancer is reported to be5.1per10,000persons. Clinical treatment and improvement of prognosis and survivaltime have been a real challenge in cancer management. Peripancreatic nerve infiltrationis a remarkable feature, which could increase the incidence rate between54%to100%[2].Published studies have proved that the nerve infiltration is closely related to clinicalsurgical timing and survival time. In recent years, many studies focus on the neuralinvasion of pancreatic cancer to explore the detailed mechanism of neural invasion.With the development of molecular techniques, the studies on cellular and molecularlevels are currently gaining due importance. Many neurotrophic factors, which areadhesion molecules produced by the nervous tissue inside and outside of pancreas, havebeen demonstrated to participate in the process of neural invasion in pancreaticcancer[3,4]. BDNF is mainly distributed in the central nervous system, peripheral nervoussystem, endocrine system, and bone and cartilage tissues[5]; and it is participated in theoccurrence of pancreatic cancer and proliferation process of tumor. Furthermore, BDNFhas some inner connections with the cancer cell metastasis and nerve invasion[3,6,7]. Therole of BDNF in nerve invasion in pancreatic cancer is not well documented. Hence, thepresent study aimed to evaluate the expression of BDNF in PDAC and determine therelationship between BDNF expression and clinicopathological characteristics ofPDAC. Objective:To determine the expression of BDNF(Brain derived neurophic factor) inpancreatic ductal adenocarcinomaand to assess the relationship between BDNFexpression and clinicopathological characteristics of pancreatic ductal adenocarcinoma.Methods:First,SP immunohistochemical staining method was used to detect the expressionof BDNF in46cases of pancreatic ductal adenocarcinoma and38cases of benignpancreatic diseases and20cases of normal pancreatic tissue,and then the Real-timePCR and Western blot respectively from the gene transcription level and protein level tovalidate its positive expression in pancreatic cancer to analyze relationship betweentheir expression and various clinic pathologic factors of pancreatic cancer especiallyrelations with perineural transfer.Results:None of the normal pancreatic tissue were BDNF positive.In46pancreatic ductaladenocarcinoma specimens,the positive expression rate of BDNF was52.2%（24/46）.BDNF expression correlated with the nerve infiltration distanceand lymphnode metastasis（P<0.05）.But not related to some clinicopathological characteristicssuch as the age,sex,size,position and differentiated degree(P>0.05). The expressionlevel of BDNF mRNA quantity respectively is expressed in pancreatic cancer tissue inthe pancreas benign disease and normal pancreas tissue2.06times and4.07times, thedifference was statistically significant(p<0.05).Conclusion:Process of BDNF in pancreatic cancer, its high expression in pancreatic cancertissue and pancreatic cancer perineural growth are closely related.