Patients with advanced cancers, for whom all standard therapy options have been exhausted, today are eligible for a broad genetic characterization of their tumor disease and - where feasible - targeted, tailor-made therapy, this takes place in so-called molecular tumor boards (MTB). MTBs have been implemented at all major cancer centers in the last few years. A persistent problem, however, is the lack of harmonization of these structures across individual locations and the hitherto missing aggregation of genetic and clinical data for scientific purposes. The Molecular Tumor Board Alliance (MTBA) of the German Cancer Consortium (DKTK) has set itself the goal of addressing these aspects in a joint effort of all DKTK partner sites by developing common binding standards for patient inclusion, genetic evaluation and visualization, therapy recommendation and follow-up. The unique collection of DKTK MTB data sets are harmonized and standardized by the MTBA and made scientifically and clinically usable via a data protection-secure cross-site query function.