GFAP and neoplasm: In comparison with subcutaneous tumors, the orthotopic KPC tumors are quite different in tumor microenvironment, as indicated in stroma cell components including pancreatic stellate cells (PSCs) and activated cancer‐associated fibroblasts (CAFs)[27] stained by glial fibrillary acidic protein (GFAP) and α‐smooth muscle actin (α‐SMA), respectively (Figure S1B, Supporting Information).