G6PD and metastatic neoplasm: In the case of A375, it is particularly striking that subcutaneous tumors formed by G6PD mutant cells grew at a similar rate as tumors formed by control cells, and yet the frequency of circulating melanoma cells in the blood, overall metastatic disease burden, and the percentage of mice that formed macrometastases were all significantly lower in mice with the G6PD mutant as compared to control cells.