ERBB2 and breast cancer: For patients with brain metastases, clinical trials have also confirmed that neratinib combined with capecitabine is effective for brain metastases in refractory HER2-positive breast cancer [34], and the specific benefit data are shown in Table 1, but about 30% of patients have adverse reactions to diarrhea, and efforts are needed to reduce diarrhea in order to better improve the quality of life of patients.