In this study, we found by integrative analyses of HR+/HER2– BC data sets from FUSCC (Fudan University Shanghai Cancer Center) (27), TCGA (The Cancer Genome Atlas), and METABRIC (Molecular Taxonomy of Breast Cancer International Consortium) that KIFC2 was amplified in approximately 50% HR+/HER2– BCs and that its high expression was associated with poor prognosis, increased tumor protein p53 (TP53) somatic mutation, and active pyrimidine metabolism. This evidence concerns the gene ERBB2 and breast carcinoma.