Robust assessment of HRD genomic instability by OncoScan microarrays

Genomic instability scars are markers for detecting homologous recombination deficiency status in ovarian cancer patients and predicting the response to PARP inhibitor treatment. Currently, only a few reliable and validated assays are available, with the Myriad myChoice CDx being the most commonly used commercial assay for genomic instability scar score determination; given the need for a more straightforward, accessible, and reliable method for detecting genomic instability scars methods. In this work we describe the feasibility of using the microarray OncoScan CNV assay and open-source software packages to quantify genomic instability scores, and the development of an open-access online platform for genomic instability score calculation. Our laboratory-developed test accurately classified homologous recombination-proficient and recombination-deficient samples based on genomic instability scores derived from the Oncoscan CNV assay. Internally evaluated genomic instability scores demonstrated a 92% overall agreement and a higher sample success rate compared to externally analyzed genomic instability scar scores. The availability of HRD determination has doubled the number of patients eligible for PARP therapy. The assay can be conveniently performed on individual samples, and the open-access online platform facilitates HRD determination without the need for specialized bioinformatics support.