Nutr Cancer. 2008 Mar-Apr;60(2):227-34. Links

Dietary berries and ellagic acid diminish estrogen-mediated mammary  tumorigenesis in ACI rats. Aiyer HS, Srinivasan C, Gupta RC. Brown Cancer Center, University of Louisville, Louisville, Kentucky 40202,  USA.
Estrogen acts as a complete mammary carcinogen in ACI rats. Prevention  studies in this model allowed us to identify agents that are effective against 
estrogen-induced mammary carcinogenesis. In this study, we investigated efficacy  of dietary berries and ellagic acid to reduce estrogen-mediated mammary  tumorigenesis. Female ACI rats (8-9 wk) were fed either AIN-93M diet (n = 25) or  diet supplemented with either powdered blueberry (n = 19) and black raspberry  (n = 19) at 2.5% wt/wt each or ellagic acid (n = 22) at 400 ppm. Animals received implants of 17beta-estradiol 2 wk later, were palpated periodically for mammary tumors, and were euthanized after 24 wk. No differences were found  in tumor incidence at 24 wk; however, tumor volume and multiplicity were  reduced significantly after intervention. Compared with the control group (average tumor volume = 685 +/- 240 mm3 and tumor multiplicity = 8.0 +/- 1.3), ellagic acid reduced the tumor volume by 75% (P < 0.005) and tumor multiplicity by 44% (P < 0.05). Black raspberry followed closely, with tumor volume diminished by > 69% (P < 0.005) and tumor multiplicity by 37% (P = 0.07).
Blueberry showed a reduction (40%) only in tumor volume. This is the first report showing the significant efficacy of both ellagic acid and berries in the prevention of solely estrogen-induced mammary tumors.