Based on function, the 12 FRGs can be grouped into four classes: Lipid metabolism (GPX4, LPCAT3, ACSL5, and ACSL6), antioxidant metabolism (CD44, SESN2, and AIFM2), iron metabolism (CISD1 and HSPB1), and cancer metabolism (SOCS1, FH, and G3BP1) [14,33-36]. The gene discussed is CD44; the disease is cancer.