TP53 and neoplasm: When the mean of the tumor volume in the control group attained about 1,000 mm3, the xenografts of the tumor volume in mice treated with metformin, IR, and a combination of both were 4.5±0.2, 48.3±6.1, and 59.0±5.0% smaller, respectively, than that of the controls at about 1,000 mm3 for HCT116 p53+/+ tumors (Fig 2C) and 26.5±1.1, 22.8±2.9, and 44.3±5.5%, respectively for HCT116 p53-/- tumors (Fig 2D).