SMAD4 and neoplasm: To clarify whether Pitx2 is a tumor suppressor in the downstream of TGF-β-Smad4 pathway in PDAC, we firstly detected the Pitx2 levels with or without inhibitors against ERK1/2 (PD98059), p38 (SB202190), TGFβ1-Smads (SB431542), and JNK (SP600125).