To further confirm the regulatory role played by endogenous FOXO3a in suppressing tumor development and growth in the orthotopic breast tumor mouse model, we generated MCF7-d8_pa cells (pooled clones of MCF-7 FOXO3a knockdown derivatives) by using retroviruses expressing short hairpin RNA against human FOXO3a (Figure 8c). This evidence concerns the gene FOXO3 and neoplasm.