Dietary energy balance modulation affects survival, tumor vascularity and proliferation. In MMTV-neu mice (A) Kaplan-Meier survival curves for CR, OW and DIO mice (n = 15 mice/diet) over a 22-month period. Mice with nontumor-related deaths (1 CR, 2 OW, and 2 DIO mice) were censored. Statistical differences in survival rate determined by log-rank test (B) Photomicrographs of mammary tumor sections stained with hematoxylin and eosin and displayed at 10x or 40x magnification. Among the tumor-bearing mice, the mammary tumors from OW (n = 12) and DIO (n = 11) mice, compared with CR mice (n = 3) were more vascular (group mean ± s.d. vascularity scores: 2.6 ± 0.18, 2.2 ± 0.25, and 1.5 ± 1.5, respectively) and consisted of more proliferating cells (group mean ± s.d. number of mitotic figures, indicated by black arrowhead: 2.6 ± 0.5, 2.4 ± 0.3 and 0.5 ± 0.4, respectively). Statistical differences in vascularity and mitotic figures determined by one-way ANOVA. *P < 0.05, **P < 0.01, ***P < 0.001.