RFXANK: A Novel Immune-Related Biomarker for Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) represents an extremely lethal malignancy on a global scale. The clinical significance and molecular mechanisms of the immune-related gene RFXANK in HCC remain unclear. This study seeks to elucidate the clinical implications and diagnostic utility of RFXANK in HCC, while further exploring its underlying molecular mechanisms. Methods: Expression differences of RFXANK in pan-cancer and HCC were analyzed using the TCGA and GEO (GSE45267) databases. Its diagnostic efficacy was evaluated by Cox regression, Kaplan-Meier survival curves, and ROC curves. Potential functional pathways were explored through GO, KEGG, and GSEA enrichment analyses. The correlation between RFXANK and immune cell infiltration, as well as immune checkpoint molecules, was analyzed using the ssGSEA algorithm and CIBERSORTx. In vitro, siRNA interference was employed to knock down RFXANK expression in Huh-7 and MHCC97H cells. The effects on cell proliferation and RAF1 protein levels were assessed using a CCK-8 assay and Western blot, respectively. Results: RFXANK was significantly overexpressed in HCC tissues and was closely associated with aggressive clinical features, including pathological T stage, histological grade, and AFP levels. Multivariate Cox regression analysis confirmed that RFXANK was an independent risk factor for survival in HCC patients (HR = 1.871). The area under the ROC curve (AUC) was 0.939, demonstrating excellent diagnostic predictive value. Enrichment analysis revealed a significant association with the cell cycle, PPAR signaling pathway, and lipid metabolism pathways. Immune infiltration analysis further revealed that RFXANK expression was significantly positively correlated with Th2 and TFH cells, as well as key immune checkpoint molecules such as PD-1, CTLA4, and LAG3, suggesting distinct features of immune polarization and an inhibitory microenvironment. In vitro cellular experiments demonstrated that knocking down RFXANK significantly inhibited the proliferative capacity of HCC cells and reduced RAF1 protein expression. Conclusions: RFXANK may promote HCC progression by driving a multidimensional proliferation-metabolism-immunity mechanism. RFXANK holds promise as a novel biomarker for diagnostic assessment and a potential therapeutic target for HCC patients.