Complex sentence: Institutions that contribute samples to TCGA are paid, and have access to molecular data generated on their samples, while maintaining a link between the TCGA unique identifier and their own unique identifier.
Split into simpler sentences: Institutions that contribute samples to TCGA are paid for their samples. In addition, the contributing institution has access to all of the molecular data generated on their samples, while maintaining a link between the TCGA unique identifier and their own unique identifier.