Through administration of EGCG and SFN as a diet for mice, it was concluded that the polyphenols had no effect on growth performance for the HER2/neu and CS (1)-SV40 Tag (C3) offspring mice, prevented ER- mammary tumorigenesis in C3 and HER2/neu mice, and increased the expression of tumor suppressors and decreased the expression of tumor-promoting proteins for C3 mice. The gene discussed is ERBB2; the disease is neoplasm.