Based on the limitations of existing studies and the needs of clinical patients, the investigators chose two time points: after the diagnosis of pancreatic cancer (before the first-line chemotherapy), and after chemotherapy evaluation in this study, to obtain in situ samples of pancreatic cancer tissues by EUS-FNA.The samples are detected by dynamic multi-omics study before and after treatment(including genomics, transcriptomics, proteomics, metagenomics, etc.).Combined with the drug reaction and clinical outcome of patients, a comprehensive model is established to predict the clinical outcome of patients with PDAC and the choice of chemotherapy regimens, so as to screen the pancreatic cancer patients who are most likely to benefit from different chemotherapy regimens, and lay the foundation for the development of individual chemotherapy for advanced pancreatic cancer.
