Homma et al. examined the methylation status of multiple regions of RUNX3 promoter CpG island (3478 bp) within the proximal promoter (No. 1–10) in gastric cancers and found that methylation at the region spanning the transcription start site (No. 5–8) is critical for loss of the RUNX3 expression (Figure 3B) [15]. Here, RUNX3 is linked to gastric cancer.