Pretreatment ctDNA findings in a cohort of 44 patients indicated that gene amplifications, particularly in FGFR1 (encoding fibroblast growth factor receptor 1) and CCNE1 (encoding cyclin E1) may serve as biomarkers for resistance to PSMA RPT (3), although these amplifications are not typically observed in tumor tissue of patients with mCRPC. The gene discussed is FGFR1; the disease is neoplasm.