G6PD and breast cancer: In addition to the NRF2-dependent antioxidant program, the overactivation of tumor growth signaling pathways, such as the EGFR/AKT pathway, the mTOR pathway, and the Wnt/β-catenin pathway, also contributes to the overexpression of G6PD, thereby conferring drug resistance, in breast cancer, lung cancer, T-cell acute lymphoblastic leukemia (T-ALL), and multiple myeloma [217,218,219].