RAD51 as biomarker for the identification of homologous recombination deficient gynaecological carcinomas

Wijk, L.M. van (2024)

Doctoral Thesis

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 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.

• Homologous recombination deficiency
• RAD51-FFPE test
• RECAP test
• BRCA1/2 deficiency
• Biomarker
• Genomic scars
• Mutational signatures
• Gynaecological carcinomas
• PARP inhibitors

• All authors: Wijk, L.M. van
• Supervisor: Devilee, P.
• Co-supervisor: Vreeswijk, M.P.G.; Vrieling, H.
• Committee: Vugt, M.A.T.M. van; Martens, J.; Wesseling, J.; Kroep, J.R.
• Qualification: Doctor (dr.)
• Awarding Institution: Faculty of Medicine, Leiden University Medical Center (LUMC), Leiden University
• Date: 2024-06-12
• ISBN (print): 9789465060996
• Sponsorship: The Dutch Cancer Society KWF/Alpe d’HuZes (grant EMCR:2014-7048 to D.C.v.G. and M.P.G.V.) and (grant 2020-1: 12995 to T. Bosse).