Automated Scoring to Assess RAD51-Mediated Homologous Recombination in Ovarian Patient-Derived Tumor Organoids

Area of Science:

• Oncology
• Genetics
• Biotechnology

Background:

• Poly(ADP-ribose) polymerase inhibitors (PARPi) enhance survival in ovarian cancers with homologous recombination deficiency (HRD).
• Current eligibility screening via next-generation sequencing has limitations due to genomic scar persistence after HR restoration or epigenetic alterations.
• Functional assays offer a more reliable method for identifying HRD tumors.

Purpose of the Study:

• To develop an automated tool for quantifying RAD51 foci in homologous recombination (HR) assessment.
• To standardize the REpair CAPacity (RECAP) test using whole slide imaging of patient-derived tumor organoids (PDTO).
• To correlate automated RECAP test results with genomic instability and clinical response.

Main Methods:

• Quantification of Cyclin A2 and RAD51 immunofluorescence in 9 ovarian PDTO models.
• Development of a quantitative histoimaging tool for automated RAD51 foci evaluation.
• Comparison of RECAP test outcomes with genome instability scores and patient clinical data.

Main Results:

• A standardized, automated quantitative histoimaging tool was developed for RAD51 foci evaluation.
• The automated RECAP-based classification correlated significantly with the genome instability score.
• The tool enables comparative RAD51 foci evaluation to define HR status in PDTO.

Conclusions:

• The developed automated tool provides a standardized method for assessing HR status in PDTO.
• This approach offers a complementary method to next-generation sequencing for identifying patients eligible for PARPi.
• Further validation on a larger patient cohort is necessary to confirm its clinical utility.