Résumé
The rationale of this work is to propose, following a bench-to-bedside approach, a state of the art with perspectives concerning homologous recombination deficiency (HRD) in ovarian cancers. Indeed, high-grade serous ovarian cancer (HGSOC), the most common and aggressive form of ovarian cancer, is characterized in half of cases by an HRD status. After defining the molecular basis of HRD, we will propose through dichotomy the different causes and consequences associated with this deficiency. Several causes have been characterized so far: these are mainly mutations in BRCA1/2 genes, but also other alterations encompassed under the concept of BRCAness. In terms of consequences, HRD leads to a specific genomic instability -or genomic scars- as well as an increased sensitivity to PARP inhibitors (PARPi). As a consequence, the presence of an HRD status is a prerequisite for the majority of current approvals for PARPi in HGSOC. As such, companion diagnostic assays turned to be necessary in a trend towards personalized medicine for patients treated for HGSOC. One of the validated approaches is based on the evaluation of the importance of genomic scars and an associated genomic instability score, indirectly reflecting the HRD status. Despite major advances, the use of HRD status remains partly controversial at present, in particular due to technical and medical limitations that we will discuss. As a consequence, several lines of research such as direct and functional evaluation of HRD status or searching for new predictive markers could in the near future lead to improvement in the selection of patients eligible for PARPi and subsequently the personalization of care.