Fig. 1

The landscape of tumor microenvironment (TME) of pancreatic cancer: (1) the PSCs, CAFs, MDSCs and TAMs promote the malignant biological behaviors of pancreatic cancer through eight aspects; (2) the phenotypes and functions of PSCs, CAFs, MDSCs and TMAs in TME of pancreatic cancer are dynamically changed and they can regulate each other; (3) bone marrow is the most importance origination for TAMs and MDSCs, and as well the bone marrow contributes to the PSCs and CAFs; (4) the cancer cells, including bulk cells and cancer stem cells (CSCs) in tumor tissue, are the main triggers to induce the architecture of TME, after chemotherapy, the damaged cancer cells, apoptotic cancer cells or immunogenic death of cancer cells can secrete varieties of signals to act on the stroma cells in TEM or to expand, recruit and activate bone marrow derived cells to remodel the TME, eventually affecting the efficacy of treatments or even leading to drug resistance