Uniform hyper- or hypomethylation was mostly present in genes that showed little or no correlation in the cross-validation (e.g. OGG1 in HNSCC and LSCC, CHEK1 in HNSCC and cervical carcinoma, HUS1 in LSCC and cervical carcinoma, Figure 4). Here, CHEK1 is linked to head and neck squamous cell carcinoma.