Rad51 clone 14b4

All hematoxylin and eosin-stained tumor-containing ovarian tissue slides were independently reviewed. The chemotherapy response score (CRS) was evaluated according to a previous study [25 (link)]. Briefly, CRS 1 indicated no or minimal tumor response, CRS 2 indicated appreciable tumor response amid a viable tumor that is readily identifiable, and CRS 3 indicated complete or near-complete response with no residual tumor or nodules up to a maximum size of 2 mm.
Conventional IHC analysis was performed on whole sections of FFPE tumor tissue blocks. Four-μm-thick sections of surgically resected tissues were immunostained using a Ventana BenchMark XT system automated stainer (Ventana Medical Systems, Tucson, AZ, USA) according to the manufacturer’s recommendations. The sections were incubated with antibodies against RAD51 (clone 14B4; GeneTex, Alton Pkwy Irvine, CA, USA), geminin (clone 10802-1-AP; ProteinTech Group, Chicago, IL, USA), and γH2AX (clone JBW301, Sigma-Aldrich, Dorset, UK). The detailed protocols are summarized in Table S1. After chromogenic visualization using an UltraView Universal DAB Detection Kit (Ventana Medical Systems), the slices were counterstained with hematoxylin, dehydrated in graded alcohols and xylene, and embedded in mounting solution. Appropriate positive and negative controls were concurrently stained to validate the staining method.