ERBB2 and breast cancer: In addition, among the 40 patients with early breast cancer and advanced/metastatic breast cancer who presented an isolated CNS relapse, 23 patients (57.5%) had HER2/neu-positive (grade 2+ and grade 3+) tumors and 11 patients (27.5%) had HER2/neu-negative (grade 0+ and grade 1+) tumors (P = 0.002).