FGFR2 and neoplasm: Truncal TP53 p.Y220C (case 5) and PIK3CA p.H1047R (case 9) mutations were identified in primary and recurrent tumors but additional mutations, MET p.T1010I, FGFR2 p.S252W, and KRAS p.G12A, were detected in the ctDNA at recurrence that were not present in the tumor samples (Table S2).