Fig. 1.

The mechanism of chemoresistance in PDAC. The epithelial–mesenchymal transition phenotype, cancer stem cells, the tumor microenvironment and the deregulation of metabolic pathways induced by chemotherapeutic agents, including changes in drug influx and efflux transporters and changes in enzymes that participate in drug effects, contribute to chemoresistance in PDAC. The arrows in black indicate shifts or bioconversion, and the upward and downward arrows in red indicate upregulation and downregulation, respectively. EMT epithelial-mesenchymal transition, CSCs cancer stem cells, TME tumor microenvironment, CAFs cancer-associated fibroblasts, TAMs tissue-associated macrophages, ROS reactive oxygen species, PSCs pancreatic stellate cells