The purpose of this study is to evaluate the prevalence of folate receptor alpha (FRα)-positive status (≥75% viable tumor cells with moderate (2+) and/or strong (3+) membrane staining) in participants with high-grade serous ovarian, fallopian tube, and primary peritoneal cancer, stratified by time of sampling (initial diagnosis versus relapse), adhering to Ventana folate receptor alpha (FOLR1) RxDx (prescription diagnosis) assay Interpretation Guidance.