CCNA1 and neoplasm: For the remaining 15 tumor tissue with detectable methylation, plasma ctDNA methylation was found in 11/15 (73.3%) of the samples, with cyclin A1 (CCNA1) exhibiting higher methylation rates (7/11), followed by TIMP metallopeptidase inhibitor 3 (TIMP3), cadherin 8 (CDH8), and death-associated protein kinase 1 (DAPK) (2/11, 1/11, and 1/11, respectively).