Influence Factors of PD-1 Therapeutic Efficacy in Advanced Pancreatic Cancer

In this study, patients with advanced pancreatic cancer who failed in the first-line chemotherapy will be included to receive anti-PD-1 monoclonal antibody treatment, and a high-throughput study with a small sample size will be carried out by using multiomics technology to capture the heterogeneity of response to PD-1 therapy in patients with pancreatic cancer.The investigators choose two time points: after chemotherapy failure (before PD-1 therapy) and during efficacy evaluation（after PD-1 therapy）, to obtain in situ samples of pancreatic cancer tissues by EUS-FNA.The samples are tested by dynamic multi-omics studybefore and after treatment (including genomics, transcriptomics, metabonomics, proteomics, etc.).And combining the results with the drug reaction and clinical outcome of patients for a comprehensive analysis.The purpose of this study is to explore the potential biomarkers or omics of PD-1 therapy and lay the foundation for building a model to predict the effect of PD-1 therapy in patients with advanced pancreatic cancer.