Following subcutaneous and orthotopic inoculation of control and genetically modified 4T-1 cells into mice, we observe that Y641-F tumor-bearing mice have significantly smaller tumors compared to control tumor-bearing mice, while EZH2 (–ΔSET) tumor-bearing mice have no significant change in the tumor growth compared to control tumor-bearing group (Fig. 1C, D and Supplementary Fig. 1) however, Y641-F tumor-bearing mice lost marked body weight compared to control, during tumor progression (Fig. 1E). The gene discussed is EZH2; the disease is neoplasm.