Proteogenomic analysis of chemo-refractory high grade serous ovarian cancer

To improve our understanding of the molecular basis of chemo-refractory high grade serous ovarian cancers (HGSOCs), we characterized the proteogenomic landscape of 242 (refractory and sensitive) HGSOCs, representing one discovery and two independent validation cohorts (spanning four academic centers) and utilizing two biospecimen types (formalin-fixed paraffin-embedded and frozen tumor biopsies). As the largest and most comprehensive study of refractory ovarian cancers to date, this effort identified a 64-protein signature that predicts a subset of HGSOCs refractory to initial platinum-based therapy with high specificity and is validated in two independent patient cohorts. We also detected significant association between lack of Ch17 loss-of-heterozygosity and refractory disease. Moreover, based on protein pathway expression, five novel clusters of HGSOC were identified and validated across two independent patient cohorts, as well as in patient-derived xenograft (PDX) models. These clusters may represent different mechanisms of refractoriness and implicate putative therapeutic targets.