Comparison of profiles between subtypes, as well as other diseases including ovarian cancer, glioblastoma multiforme (GBM), and obesity, reveals that the luminal A and luminal B subtypes of breast cancer are closer to each other than to other subtypes, luminal A and luminal B subtypes are closer to the HER2+ subtype than to the triple-negative subtype, and subtypes of breast cancer are more likely to be closer to each other than to other diseases. This evidence concerns the gene ERBB2 and breast cancer.