To investigate the functional role of TM4SF1 in pancreatic cancer cells, we transiently transfected AsPC-1, MIA PaCa-2, and PANC-1 cells with siControl and siTM4SF1 and confirmed silencing of TM4SF1 in the cells using quantitative RT-PCR, RT-PCR and western blotting (Fig 2A and S1 Fig).To evaluate the effects of TM4SF1 on cell survival and resistance to chemotherapy, we treated MIA PaCa-2, PANC-1 and AsPC-1 cells, all of which express high levels of TM4SF1 natively, with various concentration of gemcitabine in the presence of either siControl or siTM4SF1. The gene discussed is TM4SF1; the disease is familial pancreatic carcinoma.