Western blotting was applied to characterize the gene expression patterns of 4Z-B-1 cells (at P65) compared with those of other breast cancer cell lines, which were divided into the normal phenotype group (NPG), luminal phenotype group (LPG), HER2 positive phenotype group (HPG), and triple-negative phenotype group (TNPG). The gene discussed is ERBB2; the disease is breast cancer.