The American Society of Clinical Oncology and the College of American Pathologists (ASCO/CAP) proposed that HER2 negative means that a tumor with a staining score of 0 or 1+, or with a ratio of HER2 gene to chromosome 17 less than 1.8, or with four or less HER2 copy numbers per cell. Here, ERBB2 is linked to neoplasm.