Among them, seven cancer genes (ERBB2, ERBB3, PPARG, MYC, CCND1, CCNE1, MDM2) were detected to be amplified in both ctDNA and tumor tissues, indicating the reliability of ctDNA in reflecting the genomic features of tumors (Vandekerkhove et al., 2021). This evidence concerns the gene CCNE1 and neoplasm.