Autophagy-related biomarkers in hepatocellular carcinoma and their relationship with immune infiltration.

BACKGROUND: Autophagy regulation plays vital roles in many cancers. We aimed to investigate the expression, prognostic value, and immune infiltration of autophagy-related genes in hepatocellular carcinoma (HCC) by bioinformatics analysis. METHOD: Human autophagy-related differentially expressed genes (DEGs) between adjacent and HCC tissues were identified. We performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. We also evaluated immune infiltration and the response to tumor-sensitive drugs. Finally, we verified the expression of these proteins in clinical samples by immunohistochemistry (IHC), RNA isolation and real-time reverse transcription polymerase chain reaction (RT‒PCR). RESULTS: A total of 57 autophagy-related DEGs were identified. The HUB genes (BIRC5, CDKN2A, SPP1, and IGF1) were related to the diagnosis and prognosis of HCC. The HUB genes were significantly enriched in immune-related pathways. Furthermore, correlation analysis revealed that HUB gene expression was associated with immune infiltration. We identified 35 tumor-sensitive drugs targeting the HUB genes. Finally, by IHC, we discovered that the protein of CDKN2A, BIRC5, and SPP1 were upregulated in HCC tissues, while IGF1 was downregulated in HCC tissues compared with the levels in paracarcinoma tissues; by RT‒PCR, we discovered that the mRNA of CDKN2A, BIRC5, and SPP1 were upregulated in HCC tissues, while the mRNA of IGF1 was downregulated in HCC tissues compared with the levels in paracarcinoma tissues. CONCLUSION: We screened and validated four autophagy-related genes associated with immune infiltration and prognosis in patients with HCC.