This work was strongly motivated by our recent findings of aberrant activations of normally silent tissue-specific genes in breast cancer, in which DNMT3B was identified as one of the most potent prognostic biomarkers, along with four other ESC-specific genes, EXO1, MCM10, CENPF, and CENPE, and robustly associated with a high risk of patients’ relapse [9]. Here, EXO1 is linked to breast cancer.