BDNF and pancreatic adenocarcinoma: Considering the results derived from the TCGA database, the poorer prognosis was significantly associated with the elevation of BDNF expression in PAAD patients (OS: HR = 1.69, 95%CI = 1.09–2.55, p = 0.017; RFS : HR = 7.81, 95%CI = 2.19–27.87, p < 0.001; Figure 2(b)).