ABCG2 predicts the prognosis and is associated with immune infiltration in lung cancer: a bioinformatics study

Abstract Background ATP-binding cassette superfamily G member 2 (ABCG2), a member of the ATP-binding cassette transporter family, is localized in the membrane of various human cancer cells and excludes drugs from cells in an ATP-dependent manner. Its expression is linked to numerous malignant tumors. This study focused on the expression of the ABCG2 gene in lung cancer and its association with patient prognosis. Methods The expression levels of ABCG2 between lung cancer and normal tissues were explored using The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) database. The Human Protein Mapping (HPA) database was used to obtain the expression of ABCG2 protein in tissues and organs and intracellular protein expression patterns. ABCG2 was detected in the plasma membrane and nucleoplasm. University of California Santa Cruz (UCSC) and cBioPortal were used to obtain gene mapping and mutation information. The ABCG2 was significantly correlated with patient survival prognosis and immune infiltration of cancer‑associated fibroblasts in numerous types of cancer. Furthermore, Gene Ontology analysis identified that ABCG2 may be important in metabolic and cellular processes in human cancers. Results ABCG2 expression was significantly associated with multiple cancers, including lung cancer in TCGA. ABCG2 protein plays a crucial role in tumor regrowth by actively removing anticancer drugs from the cell through ABCG2-mediated efflux transport, thereby protecting against their toxic effects. The functional enrichment of ABCG2-related genes primarily involves the regulation of small GTPase-mediated signal transduction, myeloid leukocyte activation, positive regulation of cell adhesion, and endocytic vesicle localization. Additionally, it is associated with vacuolar membrane organization, lysosomal membrane organization, GTPase regulator activity, nucleoside-triphosphatase regulator activity, and small GTPase binding. Conclusion ABCG2 expression was significantly associated with poor prognosis in lung cancer patients. ABCG2 is involved in lung cancer immune infiltration and represents a suitable target for immunotherapy related to immune infiltration.