Expression of brain-derived neurotrophic factor and tyrosine kinase B receptor in pancreatic duct cancer and its clinical significance

Objective To study the expression of brain-derived neurotrophic factor (BDNF) and Tyrosine Kinase B Receptor (TrkB) in pancreatic ductal adenocarcinoma (PDAC) and it’s relationship in PDAC. Methods Collected 62 cases of PDAC paraffin samples which surgical resection was performed in Anhui provincial hospital from August 2003 to December 2015. In the study, First, according to the postoperative pathology of nerve invasion into two groups in 62 cases of pancreatic cancer specimens: Perineural invasion (PNI)-positive group (32/62) and PNI-negative group (30/62), comparative analysis of the clinical pathological characteristics, especially the relationship with perineural invasion, at the same time with 10 cases of normal pancreas tissues as control, then using immunohistochemical SP method, the Real-time polymerase chain reaction (PCR)and Western blotting separately from gene transcription level and protein level of BDNF and TrkB validated positive expression in pancreatic cancer. Results PDAC nerve invasion in the group of BDNF positive expression rate was 56.2% (18/32 cases), nerve not infringe tissues was 30.0% (9/30 cases); Nerve invasion group TrkB positive expression rate was 62.5% (20/32 cases), nerve not infringe tissues was 36.7% (11/30 cases), but not seen in 10 cases of normal pancreatic tissues of BDNF and TrkB both positive expression, and nerve infiltrating group is significantly higher than without nerve infiltration (P 0.05), adjacent to cancer cells of the nervous tissue of BDNF and TrkB positive degree higher than cancer cells from nervous tissue; Statistical analysis found that BDNF protein positive expression and the tumor diameter, tumor location, closely related to neural invasion (P<0.05); TrkB protein positive expression and the tumor location, nerve infiltration, clinical stage, lymph node metastasis (P<0.05); BDNF mRNA expression levels in pancreatic cancer, nerve invasion in the group to express quantity are not nerve invasion and normal pancreas group 2.06 times and 4.07 times, the difference was statistically significant (P<0.05); TrkB mRNA expression levels in pancreatic cancer, nerve invasion in the group to express quantity are not nerve invasion and normal pancreas group 5.41 times and 1.64 times that of comparison between groups was statistically significant (P<0.05). Conclusion This study shows that PDAC with evidence of PNI shows increased expression of BDNF and TrkB and suggests that BDNF and TrkB are involved with the mechanism leading to PNI. Key words: Pancreatic ductal adenocarcinoma; Brain-derived neurotrophic factor; Tyrosine kinase B receptor; Perineural invasion