High-grade serous ovarian cancer (HGSOC) represents 75 % of all ovarian cancer patients and is associated with poor prognosis due to its often late detection in advanced tumor stage. The current gold standard for treatment is the combination of radical cytoreductive surgery and platinum-based combination chemotherapy, though the optimal sequence of treatment modalities is still under debate. Within the AGO (Arbeitsgemeinschaft Gynäkologische Onkologie e. V.) initiated phase III trial AGO-OVAR OP.7/TRUST, 746 patients were randomized into two treatment arms, comparing the current standard of primary debulking surgery and subsequent chemotherapy with the experimental arm of neoadjuvant chemotherapy with interval debulking surgery. The SIGN-OC project was designed to analyze clinical samples from the TRUST trial to gain insights into mutational profiles analyzing molecular subtypes in predefined pathways and immune pathways, while detecting evolutionary phenotypic divergence, population distribution and specific subgroups or subclonal disease variants. We aimed to perform an integrative analysis with whole exome sequencing (WES) to study mutational processes, RNAseq to identify cellular phenotypes and a transcriptomic-/ genomic-targeted panel sequencing.