SMAD4 and familial pancreatic carcinoma: A previous study showed that genetic alterations or homozygous deletion of SMAD4 can influence the normal signalling of the TGF-β pathway and uncontrolled cell growth and pancreatic tumorigenesis [23], and low expression of SMAD4 is correlated with poor survival in pancreatic cancer, but there are very few studies on SMAD4 with chemosensitivity of gemcitabine in pancreatic cancer [24].