As shown in Figure 4, the silencing of ERRα significantly decreased the growth rate of breast cancer cell line MCF-7 (ERα-positive/HER2-negative), BT-474 (ERα-positive/HER2-positive) and SK-BR-3 (ERα-negative/HER2-positive), whereas, hardly influenced that of ERα-negative/HER2-negative breast cancer cell line MDA-MB-231. This evidence concerns the gene ERBB2 and breast cancer.