In addition, TUSC3 overexpression significantly inhibits the colony formation efficiency (274 ± 6 Vs 119 ± 4 colonies/well) in 6-well plates (p < 0.01) and reduces the size of individual colonies (p < 0.05) (Fig. 6c), suggesting that TUSC3 acts as a negative regulator of proliferation of breast cancer cells. This evidence concerns the gene TUSC3 and breast cancer.