Pan-cancer analyses reveal genomics and clinical outcome association of the fatty acid oxidation regulators in cancer.

Background: Fatty acid oxidation (FAO) is considered to play a vital part in tumor metabolic reprogramming. But the comprehensive description of FAO dysregulation in tumors has not been unknown. Methods: We obtained FAO genes, RNA-seq data and clinical information from the Msigdb, TCGA and GTEx databases. We assessed their prognosis value using univariate cox analysis, survival analysis and Kaplan-Meier curve. We determined the function of FAO genes using gene set variation analysis. The correlation analysis was calculated by corrplot R package. Immunotherapy response was assessed through TIDE scores. The protein expression levels of FAO genes were validated using immunohistochemistry (IHC). Results: The FAO scores were highest in COAD but lowest in PCPG. FAO scores were significantly associated with the prognosis of some cancers in OS, DSS, DFI and PFI. Besides, gene set variation analysis identified that FAO scores were related to immune-related pathways, and immune infiltration analysis showed FAO scores were positively related to cancer-associated fibroblasts and various immune-related genes. TIDE scores were significantly decreased in ACC, CHOL, ESCA, GBM, LAML, SARC, SKCM and THCA compared with normal samples, while it was significantly increased in BLCA, LUAD, LUSC, PCPG, PRAD and STAD. Besides, most FAO genes were downregulated in pan-cancer compared with normal samples. Moreover, we found copy number variation (CNV) of FAO genes played a positive role in their mRNA expression, while methylation was negative. We determined FAO genes were closely related to some drugs in pan-cancer. Conclusions: FAO score is a novel and promising factor for predicting outcomes.