BRCA1-mutated breast tumors are usually phenotyped as aggressive, high-grade, aneuploidy tumors (222, 223), and with a worse prognosis (224). Loss of BRCA1 function caused by BRCA1 mutation results in the production of hydrogen peroxide in both epithelial breast tumor cells and adjacent stromal fibroblasts, which is able to promote the onset of a reactive glycolytic stroma, suggesting the metabolic phenotype of stromal cells in the TME may also be affected by BRCA1 mutation in tumor cells (225). This evidence concerns the gene BRCA1 and neoplasm.