Gynaecological carcinomas (ovarian, endometrial, cervical, vaginal, vulvar and breast) are among the ones leading to the highest cancer-related deaths worldwide. The presence of germline pathogenic... Show moreGynaecological carcinomas (ovarian, endometrial, cervical, vaginal, vulvar and breast) are among the ones leading to the highest cancer-related deaths worldwide. The presence of germline pathogenic variants in the breast cancer susceptibility genes BRCA1 and BRCA2 is associated with an increased risk for breast and ovarian cancer as well as other cancers. The BRCA proteins play a crucial role in the homologous recombination (HR) pathway, which is the only DNA damage repair pathway that can repair DNA double-strand breaks error-free. The repair of DNA damage by HR is crucial to maintain genomic integrity. Patients whose tumors are HR-Deficient (HRD) are particularly sensitive to platinum-based chemotherapy and poly-ADP ribose polymerase inhibitors (PARPi). BRCA1/2 deficiency, but also (epi)genetic defects in other HR-related genes or other unknown factors can lead to HRD. However, BRCA1/2 deficiency, and not HRD, is still the leading prerequisite to be eligible for PARPi therapy. In this thesis, two functional RAD51-based HRD tests (RECAP and RAD51-FFPE test), were developed and validated using gynaecological carcinomas. These functional HRD tests were benchmarked with BRCA1/2 deficiency and with other DNA-based HRD tests measuring genomic scars and mutational signatures. In addition, the prevalence of functional HRD was explored among a variety of gynaecological carcinomas. Show less
The molecular mechanisms that instigate a healthy cell to become malignant are fueled by (epi)genetic alterations in so-called driver genes. While the Holy Grail of precision medicine is to... Show moreThe molecular mechanisms that instigate a healthy cell to become malignant are fueled by (epi)genetic alterations in so-called driver genes. While the Holy Grail of precision medicine is to identify these genetic dependencies and to target them with specific compounds in a personalized fashion, this has proven a daunting task, as tumors are exquisitely characterized by genetic instability and a mutator phenotype. Genetically engineered mouse models (GEMMs) are uniquely suited for functional in vivo validation of genotype-phenotype relationships, as they enable in vivo assessment of de novo tumorigenesis in a mammalian organism with intact immune and stromal compartments upon perturbation of (combinations of) oncogenes and/or tumor suppressor genes. Somatic modeling of cancer using CRISPR technology in vivo proved to be a true game-changing tool, allowing for rapid functional validation of candidate cancer genes enrolling from forward genetic screens and catalogs of alterations in human tumors. In this work, I showed how CRISPR approaches were deployed to precisely engineer tumorigenic events in the mouse mammary gland for dissecting oncogenic cascades, unraveling new therapeutic vulnerabilities and mechanisms of therapy resistance in different breast cancer subtypes. Show less
