YY1 and breast carcinoma: YY1 has been shown to be overexpressed in many cancers including lung cancer, breast cancer, ovarian cancer, colon cancer, prostate cancer, brain cancer, cervical cancer, osteosarcoma, gastric cancer, acute myeloid leukemia, B-cell and follicular lymphoma etc. (20, 21) and its expression levels largely correlated with cancer progression, metastasis, drug resistance, and poor prognosis.