cBioPortal is a commonly used data warehousing solution for genomic cancer studies. The software is being extended for patient care application in a molecular tumor board by the MIRACUM consortium within the Medical Informatics Initiative Germany. A key feature for this use case is the ability to enter therapy recommendations for individual patients, which requires interoperability with the hospital information system. A RESTful interface between cBioPortal and an external mediation layer was selected from the different implementation options. It achieves interoperability by using a FHIR capable server to store data and applying the HL7 FHIR Genomics Reporting implementation guide. For systems not supporting the FHIR standard, the well-established HL7 Version 2 standard is available as a fallback export format.