IFNG and cancer: More interestingly, PDT activates T lymphocytes to release IFN-γ which has been proved to downregulates both system xc- subunits (SLC3A2 and SLC7A11) at the transcriptional level, thereby causing depletion of the intracellular GSH pool and triggering ferroptosis in cancer cells (Wang et al., 2019d; Zitvogel and Kroemer, 2019).