Previous studies had demonstrated that IFN-γ synthesized by CD8+ T cells can impede system Xc- functioning by downregulating SLC7A11 and SLC3A2, two important transporter components of the glutamate-cystine antiporter system Xc−, thereby causing ROS accumulation and ferroptosis in fibrosarcoma and melanoma.22 These findings are consistent with the results of the present study; although sorafenib is a ferroptosis inducer, the degree of ferroptosis was more severe in mice treated with Efm combined with sorafenib than in those treated with sorafenib alone. This evidence concerns the gene SLC3A2 and fibrosarcoma.