Bisulfite-sequencing PCR (BSP)
The DNA from the MSP results was subjected to sodium bisulfite treatment via a DNA bisulfite kit (Qiagen, Beijing, China) according to the manufacturer’s instructions. After bisulfite conversion, the DNA was purified and recovered via the SanPrep Column DNA Gel Extraction Kit (Sangon, Shanghai, China). Primers for bisulfite pyrosequencing were designed to target the specific region of interest and were utilized with 3730 sequencing analyzers. The primers for the TP53BP2 methylation reaction were as follows: TP53BP2 forward: 5′-AACTTCACGGTGGGTTTCAAGC-3′; TP53BP2 reverse: 5′-GTGCAGGCCTGAGCCTTCT GGC-3′.