Dietary phytosterol inhibits the growth and metastasis of MDA-MB-231 humanbreast cancer cells grown in SCID mice

The objective of the present study was to investigate the effect of dietary phytosterols on the growth and metastasis of the human breast cancer MDA-M B-231 cell line xenografted in SCID mice. Two groups of animals were fed AI N-93G diet supplemented with 0.2% cholic acid and 2% sterol (cholesterol or phytosterol mixture) for 15 days before inoculation of the tumor into the right inguinal mammary fat pad. Tumor growth and food consumption were reco rded weekly throughout the 8 weeks of the experiment. At the end of the exp eriment, the animals fed phytosterol had a 40% lower serum cholesterol and 20 and 30 fold higher serum beta-sitosterol and campesterol, respectively a s compared to those fed cholesterol. There was no difference between the tw o groups in body weight and food consumption. However; the armor size in an imals fed phytosterols was 33% smaller (P<0.03) and had 20% fewer metastase s to lymph nodes and lungs than the cholesterol group. At termination, the tumor weight of the animals fed the phytosterol diet was also less (P<0.07) than that of the cholesterol group. It is concluded that dietary phytoster ols retard the growth and spread of breast cancer cells.