ERBB2 and chronic myelogenous leukemia, BCR-ABL1 positive: For example, imatinib is used to treat BCR-ABL tyrosine kinase constitutively activated chronic myeloid leukemia (14), HER2 protein-targeting drugs are used to treat HER2-positive breast cancer (15), and estrogen antagonists are used to treat estrogen receptor-positive breast cancer (16).