A study conducted by Guo et al. [35] found a comparatively higher proportion of p16 (52%) and a lower percentage of DAPK (24%) promoter hypermethylation in ESCC tumours, which might be due to ethnic variations; however, they reported a similar proportion of BRCA1 promoter methylation (28%). Here, BRCA1 is linked to esophageal squamous cell carcinoma.