Sung et al. (2020) reported that triple negative breast cancer-derived exosomal Integrin beta 4 (ITGB4) induces a metabolic reprogramming in cancer-associated fibroblasts (CAFs) that, in turn, supports tumor progression. Exosomal ITGB4 triggers the conversion of pyruvate to lactate in CAFs via BCL2 Interacting Protein 3 Like (BNIP3L)-dependent mitophagy. The gene discussed is ITGB4; the disease is cancer.