The gene-specific DNA methylation patterns from normal epithelium and paired cancer tissues from six patients with HNSC were assessed using NGS-BSP which was completed using a previously published method (17 (link),21 (link),22 (link)). Briefly, BSP primers were designed using online MethPrimer software and were listed in Table S2. Genomic DNA (1 μg) was converted to template using ZYMO EZ DNA Methylation-Gold Kit (Zymo Research, Irvine, CA, USA), and one twentieth of the elution products were used as templates for the 35 cycle PCR amplifications completed using KAPA 2G Robust HotStart PCR Kit (Kapa Biosystems, Wilmington, MA, USA). The BSP products of multiple genes were then pooled, 5'-phosphorylated, 3'-dA-tailed and ligated to barcoded adapters using T4 DNA ligase (New England Biolabs, Ipswich, MA, USA). Barcoded libraries from each of the samples were then sequenced using an Illumina platform. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the Medical Ethics Committee of the West China Hospital of Stomatology, Sichuan University (No. WCHSIRB-ST-2016-153) and informed consent was taken from all the patients.