Fibroblast activation protein (FAP) as a prognostic biomarker in multiple tumors and its therapeutic potential in head and neck squamous cell carcinoma

摘要

Background:Fibroblast activation protein(FAP),a cell surface serine protease,plays roles in tumor invasion and immune regulation.However,there is currently no pan-cancer analysis of FAP.Objective:We aimed to assess the pan-cancer expression profile of FAP,its molecular function,and its potential role in head and neck squamous cell carcinoma(HNSC).Methods:We analyzed gene expression,survival status,immune infiltration,and molecular functional pathways of FAP in The Cancer Genome Atlas(TCGA)and Genotype Tissue Expression(GTEx)tumors.Furthermore,to elucidate the role of FAP in HNSC,we performed proliferation,migration,and invasion assays post-FAP overexpression or knock-down.Results:FAP expression was elevated in nine tumor types and was associated with poor survival in eight of them.In the context of immune infiltration,FAP expression negatively correlated with CD8+T-cell infiltration infive tumor types and positively with regulatory T-cell infiltration in four tumor types.Our enrichment analysis highlighted FAP’s involvement in the PI3K-Akt signaling pathway.In HNSC cells,FAP overexpression activated the PI3K-Akt pathway,promoting tumor proliferation,migration,and invasion.Conversely,FAP knockdown showed inhibitory effects.Conclusion:Our study unveils the association of FAP with poor tumor prognosis across multiple cancers and highlights its potential as a therapeutic target in HNSC.