Recent changes in data management within post-genomic clinical trials have emphasized the need for novel methods and tools to solve semantic and syntactic heterogeneities among distributed sources of information. ACGT is an Integrated Project funded by the European Commission that aims at building a GRID-based platform comprised by a set of tools to support multi-centric post-genomic clinical trials on cancer. The main goal of ACGT is to provide seamless access to heterogeneous sources of information. For this purpose, two core tools were developed and included in the ACGT architecture: the ACGT Semantic Mediator (ACGT-SM), and the Data Access Wrappers (ACGT-DAWs). The ACGT-SM addresses semantics and schema integration, while the ACGT-DAWs cope with syntactic heterogeneities. Once the sources are bridged together, they can be seamlessly accessed using the RDQL query language.We tested our tools using a set of three relational and DICOM based image sources obtaining promising results.