NOS2 and breast cancer: Overexpression of iNOS, neuronal nitric oxide synthase (nNOS), Kelch-like ECH-associated protein 1 (KEAP1), NADPH Oxidase 4 (NOX4), and TGR5 or downregulation of nuclear factor erythroid 2-related factor 2 (NRF2) was associated with improved survival in BC patients, except for those with triple-negative disease.