Intriguingly, these 11 probes were all located in the PGK1 promoter regions, ranging from 500 nt upstream of the transcription start site (TSS500) to the 5′-untranslated region (5′-UTR) (Additional file 1: Table S2; Additional file 1: Fig. S3), indicating that the PGK1 promoter regions were hypomethylated in these five types of cancer. The gene discussed is PGK1; the disease is cancer.