This article describes the process of defining and implementing new components to exchange data between two real GRID-based platforms for breast cancer diagnosis. This highly collaborative work in development phase pretends to allow communication between middleware, namely TRENCADIS and DRI, in different virtual organizations. On the one hand, TRENCADIS is a Service-Oriented Architecture in which the usage of resources is represented with Grid services based on the Open Grid Service Architecture specification (OGSA).On the other hand, DRI is a software platform aimed at reducing the cost of hosting digital repositories of arbitrary nature on Grid infrastructures. TRENCADIS has been deployed in the Dr. Peset Hospital (Valencia, Spain) and DRI has been deployed in the São João Hospital (Porto, Portugal). The final objective of this work in progress is to share medical images and its associated metadata among geographically distributed research institutions, while maintaining confidentiality and privacy of data.