S2
Briefly, cfDNA was purified. Then, the selective 5hmC chemical labeling was performed. After cfDNA purification, the biotin-labeled cfDNA was pulled down using C1 Streptavidin beads (Life Technologies). Next, the captured cfDNA was amplified and purified. The libraries were quantified by a Qubit fluorometer (Life Technologies, CA, USA). The library preparations were sequenced on the Illumina Novaseq platform, and 150 bp paired-end reads were generated.