ABSTRACT
ObjectiveTo evaluate the expression level of DNA damage repair gene FANCI in hepatocellular carcinoma （HCC） and its relationship with prognosis， clinical stage and immune infiltration. MethodsIn this study， TCGA， GTEx， TIMER2.0， HPA database and qRT-PCR， western blot and immunohistochemistry were used to analyze the expression of FANCI in HCC and its correlation with different clinical stages； Kaplan-Meier Plotter database was used to explore the relationship between FANCI and the prognosis of HCC； the TISIDB database was used to analyze the relationship between FANCI and immune cell infiltration and immune checkpoints in HCC； the STRING database was used to detect the protein binding with FANCI； the TCGA and GTEx databases were used for GO and KEGG enrichment analysis； Cell experiments were used to explore the role of FANCI in HCC. ResultsCompared with normal tissues， the mRNA and protein expression levels of FANCI in tumor tissues were up-regulated （P<0.001）； and HCC patients with high expression of FANCI had poor prognosis （P<0.001）； the expression of FANCI in tumor tissues was positively correlated with the number of activated CD4+ T cells， the number of Th2 cells and the expression of immune checkpoints， and B-cell and macrophage infiltration was significantly lower in the FANCI high expression group （P<0.01）； GO and KEGG enrichment analysis showed that FANCI-related genes were enriched in various biological processes such as amino acid transmembrane transporter activity； Cell experiments showed that knockdown of FANCI could inhibit the proliferation， invasion and migration of HCC （P<0.05）. ConclusionsFANCI is highly expressed in hepatocellular carcinoma tissues， which may play a role in suppressing anti-tumor immunity and acting on pathways such as amino acid transmembrane transport， and is associated with poor prognosis. The proliferation， invasion and migration ability of hepatocellular carcinoma are inhibited after knocking down FANCI.