Previous studies have shown that ErbB2 is located in the nucleus and acts as a transcription regulator to activate the transcription of COX-2 by directly binding to the HAS in its promoter7, or to enhance rRNA synthesis by promoting the binding of RNA Pol I to rDNA8, etc. Further studies revealed that nuclear ErbB2 is involved in breast cancer cell growth, metastasis, and drug resistance, and it is being validated as a novel therapeutic target in ErbB2-positive breast cancer11. This evidence concerns the gene ERBB2 and breast cancer.