In comparison with normal tissues, three biomarkers, CCDC181, GCM2 and ITPRIPL1, were found to be simultaneously hypermethylated only in breast tumors in TCGA and Taiwanese patients, but not in lung cancer, uterine cancer, ovarian cancer, gastric cancer, esophagus cancer, pancreatic cancer, liver cancer or colorectal cancer (Figure 2 and Table S5). Here, GCM2 is linked to colorectal cancer.