High TLX1 Expression Correlates with Poor Prognosis and Immune Infiltrates in Patients with Lung Adenocarcinoma

Background: To develop optimal personalized therapy for lung adenocarcinoma (LUAD), potential biomarkers associated with the prognosis are urgently needed. It is unclear what role T Cell Leukemia Homeobox 1 (TLX1) plays in LUAD. Objective: In this study, TLX1's relationship with LUAD was investigated using TCGA database analysis, bioinformatics analysis, and experimental validation. Methods: We examined the expression of TLX1 in pan cancer and LUAD, the relationship between TLX1 expression and clinical features, immune infiltration, its diagnostic and prognostic value, as well as TLX1 related pathways. The analysis included various statistical methods, including the Kaplan-Meier method, Cox regression analysis, GSEA, and immune infiltration analysis. TLX1 expression in LUAD cell lines was validated using qRT-PCR. Result: In LUAD patients, high expression of TLX1 was associated with T stage (P<0.001). High TLX1 expression was associated with worse overall survival (OS) (HR: 1.57; 95% CI: 1.18–2.1; P=0.002). And TLX1 HR: 1.619; 95% CI: 1.012-2.590; P=0.044) was independently correlated with OS in LUAD patients. TLX1 expression was associated with the pathways, including Rho GTPase effectors, DNA repair, TCF dependent signaling in response to WNT, signaling by Nuclear Receptors, signaling by Notch, chromatin-modifying enzymes, ESR-mediated signaling, cellular senescence, and transcriptional regulation by Runx1. TLX1 expression was correlated with aDC, Tcm, and TReg cells. The expression of TLX1 was significantly increased in LUAD cells compared to BEAS-2B cells. Conclusion: An association between high TLX1 expression and poor survival and immune infiltration was found in LUAD patients. There may be a potential role for TLX1 in diagnosis, prognosis, and immunotherapy for LUAD.