By integrating gene expression data and tissue-based breast cancer necrosis information, we obtained a novel Breast Cancer Necrosis Signature (BCNS) score that demonstrated associations with aggressive tumor features and independent prognostic value, also in the subset of patients with hormone receptor positive luminal tumors, pointing to an added value of the BCNS score to the PAM50 algorithm as prognosticator. This evidence concerns the gene NR4A1 and breast cancer.