BackgroundChemokine ligand 14, which has a C–C motif (CCL14), mediates the immunological milieu around tumors. However, its role in the progression of lung adenocarcinoma (LUAD) is still unknown. Our objectives were to study the association between CCL14 and tumor-infiltrating immune cells (TIICs) as well as the predictive significance of CCL14 in LUAD.MethodsThe expression of CCL14 in LUAD was examined by using the Oncomine, The Cancer Genome Atlas (TCGA), The University of Alabama at Birmingham CANcer data analysis Portal (UALCAN), and Human Protein Atlas databases. To determine the prognostic significance of CCL14 in LUAD, researchers used the Kaplan‒Meier plotter and Gene Expression Profiling Interactive Analysis (GEPIA, version 2). We utilized TIMER and GEPIA2 to investigate the connection between CCL14 and TIICs. Gene set enrichment analysis (GSEA) was used to test for functional enrichment of genes. We used RT‒qPCR to measure CCL14 expression and Cell Counting Kit-8, Transwell, and wound healing assays to investigate the biological role of CCL14.ResultsThe prognosis of patients with LUAD was worse when CCL14 expression was low. Statistical analysis revealed that CCL14 mRNA expression was significantly greater in lung epithelial cells than in LUAD cell lines in vitro. Enhancing CCL14 expression reduced cell migration, invasion, and proliferation. The results of the immune infiltration research showed that CCL14 and TIICs were positively correlated. Different immune infiltration patterns associated with CCL14 were also shown by TIIC markers. According to GSEA, histone deacetylases, G2/M checkpoints, and Notch signaling pathways were associated with low CCL14 expression.ConclusionsCCL14 is anticipated to emerge as a prognostic marker and therapeutic target for LUAD due to its role in regulating TIICs, suggesting that it may be an antioncogene.