MKI67 and metastatic malignant neoplasm in the lymph nodes: As shown in Table 2, patients with younger age (<60 years; P < 0.0001), negative PR expression (P = 0.0028), higher Ki67 expression levels (P < 0.0001), and absence of lymph node metastasis (P < 0.0001) were more likely to benefit from pyrotinib treatment.