This open-label, multicenter, non-randomized phase I trial of gemcitabine plus once and twice daily dasatinib is designed to assess the safety, tolerability, maximum tolerated dose/recommended phase II dose, and preliminary efficacy of this combination in adult patients with advanced solid tumors and with previously untreated metastatic pancreatic cancer. Patients will be accrued at Duke University Medical Center, the Duke Oncology Network, the University of North Carolina at Chapel Hill and Wake Forest Baptist Medical Center