Even though the risk models for the tumor microenvironment, immune cell infiltration, and energy metabolism of LUAD have been reported (37–39), we constructed a 9-gene prognostic risk model based on CYP4B1, KLF4, DPEP2, PTGDS, CYP27A1, ACSS3, HSD17B13, HPGDS, and FA2H, which was validated by an external dataset. This evidence concerns the gene KLF4 and neoplasm.