The objectives of this study are to assess the safety and tolerability of the combination of Decitabine with Gemcitabine in previously treated patients with advanced pancreatic cancer and advanced sarcoma and to define the recommended Phase II dose and describe the dose-limiting toxicity of the combination of Decitabine with Gemcitabine. The preliminary efficacy parameters of the combination of Decitabine with Gemcitabine will be estimated in terms of response rate and disease control rate and progression-free survival.