Pan-Cancer Analysis of ABCA3: Insights into Prognosis, Epigenetic Regulation, and Immune Microenvironment

The ATP-binding cassette subfamily A member 3 (ABCA3) gene encodes a transmembrane protein that facilitates lipid transport and regulates lung surfactant levels. The gene functions as a tumour suppressor, but its involvement in different cancer types has not been fully elucidated. This study assessed ABCA3 expression as a potential predictive marker across several cancer types. We also investigated its influence on immune cell infiltration and epigenetic alterations, with a particular focus on lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). ABCA3 gene expression was investigated through a pan-cancer analysis utilizing several bioinformatics databases, including GEPIA, TIMER2, UALCAN, CbioPortal, GSCA, and the Kaplan-Meier plotter. The promoter region of ABCA3 showed hypermethylation in LUAD and LUSC, which decreased gene expression. The survival analysis demonstrated that LUAD patients, along with several other cancer types, experienced better survival outcomes when ABCA3 expression levels were high, but LUSC patients showed worse survival results when ABCA3 expression was elevated. The expression levels of ABCA3 in LUAD showed a positive correlation with CD4⁺ T cell and CD8⁺ T cell infiltration. The study shows that ABCA3 acts as a tumour suppressor and immune-associated biomarker, mainly in lung cancer, and has potential for prognostic evaluation and therapeutic strategies.