Bioinformatics-Based Characterization of ATP-Binding Cassette Subfamily B Member 1 (ABCB1) Gene Expression in Non-Small-Cell Lung Cancer (NSCLC)

P-glycoprotein (P-gp) has been implicated in lung cancer development, disease progression, and patient survival. Changes in the ABCB1 expression level may correlate with tumorigenesis and the formation of multidrug resistance (MDR). In addition, epigenetic modifications such as DNA methylation are involved in the regulation of the transcriptional activity of this gene. Therefore, we focused on an analysis of changes in the expression of ABCB1 and its methylation, taking into account their potential associations with the clinicopathological parameters of LUAD and LUSC. The TNMplot, UALCAN, cBioPortal, PrognoScan, and MEXPRESS databases were used to investigate the role of this gene in lung cancer progression. ABCB1 expression in lung tissue was significantly downregulated in cancer cells, but differences also resulted from age, gender, ethnicity, and smoking cessation. Moreover, decreased levels of gene transcript were associated with both a higher stage of cancer and a lower probability of survival. It is worth emphasizing that the presence/direction of ABCB1 expression changes are frequently unique to specific histological tumor subtypes. Finally, it is equally important that the main methylation promoter is one of the causes of decreased gene expression in lung cancer cells. Taken together, these data establish the ABCB1 transporter gene as an important prognostic factor that could alter disease progression and contribute to the survival of cancer patients.