Downregulation of NUPR1 by siRNA decreased the amount of both the ERBB2 mRNA transcripts and the ERBB2 proteins present in the ER+ ERBB2high MCF7-TamC3 and the ER- ERBB2high (ERBB2-enriched subtype-like) SK-BR-3 breast cancer cells (Fig. 4G and 4H). This evidence concerns the gene ERBB2 and breast cancer.