Fig. 1

The graphic abstract of PDAC TME.• From the right upper side to the left low side, we summarize the progression of PDAC from PanIN and the distribution of different cells in TME. The yellow area represent the area mainly comprising different advanced stage of epithelial tissue from normal acinar to PanIN and invasive cancer nest, as well as monocyte-like cells; the reddish area present the area comprising mainly matrix including fibrotic matrix, pancreatic stellate cells, cancer associated fibroblasts, TLS, as well as accumulated effector lymphocytes. The cancer nests look like islands in the stroma desert; Treg cells surround the PanIN and establish a TSA specific suppressive condition to support PDAC progression; MDSCs appear at very early stage of the PDAC progression and disperse the whole lesion of tumor; TAMs locate majorly at the invasive front of the tumor and promote angiogenesis, lymphogenesis and metastasis; DCs are scarce and restricted in PanIN and TLS; CAFs and PSCs are the major source of tumor stromal matrix, they can also adhere infiltrating T lymphocytes, keep them outside of cancer nest and result effector T cell anergy; TLS localize in the tumor stroma and consist of proliferating effector cells as well as Treg cells, tumor specific anti-tumor and pro-tumor reactivity present concordantly