TCF3 as a multidimensional biomarker: oncogenicity, genomic alterations, and immune landscape in pan-cancer analysis.

Transcription factor 3 (TCF3), a pivotal member of the TCF/LEF family, plays a critical role in tumorigenesis. Nonetheless, its impact on the tumor microenvironment (TME) and cancer phenotypes remains elusive. We perform an exhaustive analysis of TCF3 expression, DNA variation profiles, prognostic implications, and associations with the TME and immunological aspects. This study is based on a large-scale pan-cancer cohort, encompassing over 17,000 cancer patients from multiple independent datasets, validated by in vitro assays. Our results show that TCF3/4/7 exhibits differential expression patterns between normal and tumor tissues across pan-cancer analyses. Mutational analysis of TCF3 across diverse cancer types reveals the highest alteration rates in biliary tract cancer. Additionally, mutations and single nucleotide variants in TCF3/4/7 are found to exert varied effects on patient prognosis. Importantly, TCF3 emerges as a robust predictor of survival across all cancer cohorts and among patients receiving immune checkpoint inhibitors. Elevated TCF3 expression is correlated with more aggressive cancer subtypes, as validated by immunohistochemistry and diverse cohort data. Furthermore, TCF3 expression is positively correlated with intratumoral heterogeneity and angiogenesis. In vitro investigations demonstrate that TCF3 is involved in epithelial-mesenchymal transition, migration, invasion, and angiogenesis. These effects are likely mediated through the interaction of TCF3 with the NF-κB/MMP2 pathway, which is modulated by IL-17A in human uveal melanoma MUM2B cells. This study elucidates, for the first time, the significant associations of TCF3 with DNA variation profiles, prognostic outcomes, and the TME in multiple cancer contexts. TCF3 holds promise as a molecular marker for diagnosis and as a potential target for novel therapeutic strategies, particularly in uveal melanoma.