SMAD4 and pancreatic neoplasm: Therefore, to further investigate the antitumor effects of DTLL in combination with gemcitabine, we selected two PDX models (PA1233 and PA3142) as SMAD4-mutant/deficient and SMAD4-wild-type/sufficient models, based on SMAD4 genetic status obtained from available RNA sequencing datasets (https://models.crownbio.com/pancreatic-cancer/) and protein levels by using Western blot assays (Fig. S1b).