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. Here, SLC7A11 is linked to fibrosarcoma.