In order to rule out the possibility that the presence of the amplicons is a surrogate for high histologic grade, a multivariate Cox analysis (Table 3) was performed on the training data set (GEO accession number GSE6532) to explore the relation between the presence of any of the four amplicons and other clinical markers (patient age, tumor size, node status, tumor grade and HER2 status) as well as the relative Oncotype Dx score calculated from gene expression data. Here, ERBB2 is linked to neoplasm.