At time-of-sacrifice (i.e., a tumor volume of 1500 mm3), tumor cell proliferation (as measured by the relative number of Ki67-positive nuclei in the tumor) was visually, but not significantly decreased in radiotherapy-treated (55% ± 10%) and combination-treated (55% ± 15%) animals compared to controls (75% ± 5%) and metformin-treated (68% ± 3%) animals (p = 0.4; Fig. 4a, b). The gene discussed is MKI67; the disease is neoplasm.