Fig. 1: Experimental roadmap of the study.

a Flow chart of participants. b Schematic diagram of the FFPE-RRBS protocol. Genomic DNA was isolated from FFPE tissue. The degraded genomic DNA was then end-polished by dephosphorylation. Subsequent enzymatic reactions, including MspI digestion, end-repair, A-tailing, and adapter ligation, were performed in the same tube without DNA cleanup. After bisulfite conversion, the library DNA was enriched by PCR and sequenced on an Illumina NovaSeq 6000 sequencer.