Unveiling FAM111B: A Pan-Cancer Biomarker for DNA Repair and Immune Infiltration

Recent evidence indicates that FAM111B is significantly involved in the progression of various cancers. Nonetheless, the potential pan-cancer implications of FAM111B have not been systematically investigated. In this study, FAM111B’s expression and oncogenic potential were studied using TCGA and GTEx data via GEPIA2, TIMER2.0, and STRING tools. Pathway enrichment analyses with the GO, KEGG, Reactome, and WikiPathways databases were conducted to explore its role in cancer development. The results were validated via multiplex immunofluorescence assays of pancreatic cancer tissues, microarray assays of ovarian cancer tissues, and protein transcriptomics of ovarian cancer cells. The expression levels of FAM111B were elevated in most cancer types and were associated with poor prognostic outcomes. Mechanistically, FAM111B expression was positively correlated with the expression of genes involved in DNA homologous recombination repair and with the infiltration of Th2 CD4+ T cells. These observations were further substantiated in ovarian cancer cell lines and tissue specimens from pancreatic and ovarian cancers. FAM111B functions as a biomarker for the DNA repair pathway and Th2 CD4+ T-cell infiltration in human malignancies.