ERBB2 and breast cancer: In addition, the classification of BC into HER2-positive or -negative subtypes shows among HER2-overexpressed tumors the same trend for bone metastases (thus exploring the implication that luminal A tumors were significantly associated with bone metastases, OR: 0.294), as well for distant nodal relapse rate (OR: 2.65) although with a less significant result, but with a relevant higher incidence of CNS metastases, OR: 5.6 (p: 0.003).