MUS81 and breast cancer: 10 have showed that 73% of Mus81−/− mice and 50% of Mus81+/− mice died of various spontaneous tumors such as lymphoma, breast cancer, and prostate cancer, therefore Mus81 was traditionally regarded as a potent tumor suppressor. Our previous studies also demonstrated that the downregulation of Mus81 in HCC, colorectal cancer, and gastric cancer was closely correlated with the progression and prognosis of these malignancies 11, 12, 13, 14.