Objective: To analyze the expression levels of the F9 gene and F9 protein in hepatocellular carcinoma by combining multiple gene chip data, real-time fluorescence quantitative PCR (RT qPCR), and immunohistochemistry. Additionally, explore their correlation with the occurrence and development of hepatocellular carcinoma, as well as with various clinical indicators and prognosis. Methods: The mRNA microarray dataset from the GEO database was analyzed to identify the F9 gene with significant expression differences associated with hepatocellular carcinoma. Liver cancer and adjacent tissues were collected from 18 cases of hepatocellular carcinoma. RT-qPCR method was used to detect the F9 gene expression level. Immunohistochemistry was used to detect the F9 protein level. Combined with the TCGA database information, the correlation between F9 gene expression level and prognostic and clinicopathological parameters was analyzed. The biological function of F9 co-expressed genes associated with hepatocellular carcinoma was analyzed by the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). Statistical analysis was performed using Graphpad Prism software. Results: Meta-analysis results showed that the expression of the F9 gene was lower in HCC tissues than in non-cancerous tissues. Immunohistochemistry results were basically consistent with those of RT-qPCR. The data obtained from TCGA showed that the F9 gene had lower expression values in stages III-IV, T3-T4, and patients with vascular invasion. A total of 127 genes were selected for bioinformatics analysis as co-expressed genes of F9, which were highly enriched in redox processes and metabolic pathways. Conclusion: This study validates that the F9 gene and F9 protein are lower in HCC. The down-regulation of the F9 gene predicts adverse outcomes, which may provide a new therapeutic target for HCC.
目的： 应用生物信息学技术筛选出肝细胞癌组织中的低表达基因F9，通过汇合多个基因芯片数据、实时荧光定量PCR（RT-qPCR）及免疫组织化学分析F9基因和F9蛋白在肝细胞癌中的表达水平，探索其与肝细胞癌发生发展及与各个临床指标和预后的相关性。 方法： 通过分析GEO数据库中mRNA微阵列数据集,获取与肝细胞癌相关的具有明显表达差异的基因F9;收集18例肝细胞癌患者的肝癌及癌旁组织,采用RT-qPCR法检测F9基因表达水平，免疫组化用于检测F9蛋白水平;结合TCGA数据库信息,分析F9基因表达水平与预后及临床病理参数之间的相关性。通过基因本体论（GO）、京都基因与基因组百科全书（KEGG）对肝细胞癌相关的F9共表达基因进行生物功能分析。采用Graphpad Prism软件进行统计学分析。 结果： Meta分析结果表明肝细胞癌组织中F9基因的表达低于非癌组织。免疫组织化学结果与RT-qPCR基本一致。从TCGA中获取的数据表明F9基因在Stage III~IV、T3~T4期以及有血管侵犯的患者中有更低的表达值。生物信息学分析共选择127个基因作为F9的共表达基因，在氧化还原过程和代谢途径中高度富集。 结论： F9基因及F9蛋白在肝细胞癌中低表达；F9基因下调预示不良结局，可能为肝细胞癌提供了一个新的治疗靶点。.
Keywords: Bioinformatics; F9 gene; Gene chips; Hepatocellular carcinoma; Public data platform.