NR4A1 and breast carcinoma: Multiple studies using different platforms and methodologies have revealed that basal-like breast carcinomas are generally characterized by negative expression of hormone receptors and related genes, as well as positive expression of a set of genes typically associated with basal epithelial cells, such as basal cytokeratins, P-cadherin, β4 integrin and nestin, in addition to several genes involved in cellular proliferation [1,2,19].