1. The RAD51-FFPE test
- Author
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Katja N. Gaarenstroom, Claire J H Kramer, Lise M van Wijk, Tjalling Bosse, Harry Vrieling, Cor D. de Kroon, Judith R. Kroep, S. Vermeulen, Marthe M de Jonge, Natalja T. ter Haar, and Maaike P.G. Vreeswijk
- Subjects
0301 basic medicine ,Cancer Research ,DNA damage ,RAD51-FFPE test ,RAD51 ,endometrial carcinoma ,Article ,03 medical and health sciences ,Ovarian tumor ,0302 clinical medicine ,Ovarian carcinoma ,Medicine ,RC254-282 ,business.industry ,Endometrial cancer ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RECAP test ,BRCA1 ,medicine.disease ,BRCA2 ,ovarian carcinoma ,030104 developmental biology ,Oncology ,homologous recombination deficiency ,030220 oncology & carcinogenesis ,PARP inhibitor ,Cancer research ,Homologous recombination ,business ,Ex vivo - Abstract
Simple Summary Rapid and reliable identification of patients with homologous recombination deficient (HRD) tumors is important for treatment choice as these tumors tend to respond well to platinum-based chemotherapy and PARP inhibitors (PARPi). In this study, a RAD51-based functional HRD test that can be performed on routine diagnostic formalin-fixed paraffin-embedded (FFPE) tissues (RAD51-FFPE test), was further improved and optimal test parameters were determined. The RAD51-FFPE test was able to determine tumor HR status with high sensitivity and specificity, making it an attractive test to be applied as routine diagnostic tool in the near future. Abstract PARP inhibitor (PARPi) sensitivity is related to tumor-specific defects in homologous recombination (HR). Therefore, there is great clinical interest in tests that can rapidly and reliably identify HR deficiency (HRD). Functional HRD tests determine the actual HR status by using the (dis)ability to accumulate RAD51 protein at sites of DNA damage as read-out. In this study, we further improved and calibrated a previously described RAD51-based functional HRD test on 74 diagnostic formalin-fixed paraffin-embedded (FFPE) specimens (RAD51-FFPE test) from endometrial cancer (EC n = 25) and epithelial ovarian cancer (OC n = 49) patients. We established optimal parameters with regard to RAD51 foci cut-off (≥2) and HRD threshold (15%) using matched endometrial and ovarian carcinoma specimens for which HR status had been established using a RAD51-based test that required ex vivo irradiation of fresh tissue (RECAP test). The RAD51-FFPE test detected BRCA deficient tumors with 90% sensitivity and RECAP-HRD tumors with 87% sensitivity, indicating that it is an attractive alternative to DNA-based tests with the potential to be applied in routine diagnostic pathology.
- Published
- 2022