G6PD and breast carcinoma: Even though in our cells, 6PGD knockdown did not cause a strong G6PD activity enhancement, knowing that breast cancer cells have a very active PPP and that especially MCF7 cells have very high G6PD levels, we assume that NADPH produced by G6PD together with enhanced glutaminolysis is enough to compensate the decrease of NADPH resulting from the reduced 6PGD activity as well as to maintain ROS levels.