Oncogenic MYC expression in breast cancer cells induces expression and EV packaging of miR-105 that, when taken up by recipient fibroblasts, induces a metabolic shift. Reprogrammed fibroblasts increase glucose and glutamine metabolism and detoxify metabolic wastes (lactate, ammonium) and convert them into energy-rich metabolites for cancer cells. This evidence concerns the gene MYC and breast carcinoma.