In univariate analysis, larger tumor size, node-positive disease, negative hormone receptor status (both estrogen and progesterone negative), poor tumor differentiation (G3 tumor, high Ki67), HER2-positive or triple-negative tumor subtype, and no pCR after neoadjuvant chemotherapy were significantly associated with the occurrence of CNS metastases as the first site of metastatic disease. The gene discussed is MKI67; the disease is metastatic neoplasm.