The relationship between YY1 and SOX2 expressions as well as the expressions of BMI1 and OCT4 resulted in the classification of four groups of cancers with distinct molecular signatures: 1) Prostate, lung, cervical, endometrial, ovarian and glioma cancers (YY1loSOX2hiBMI1hiOCT4hi) 2) Skin, testis and breast cancers (YY1hiSOX2loBMI1hiOCT4hi) 3) Liver, stomach, renal, pancreatic and urothelial cancers (YY1loSOX2loBMI1hiOCT4hi) and 4) Colorectal cancer, lymphoma and melanoma (YY1hiSOX2hiBMI1loOCT4hi). Here, YY1 is linked to breast cancer.