Differential expression profiles and functional prediction of circular RNAs in lung cancer patients with chronic obstructive pulmonary disease: a pilot study.

Chronic obstructive pulmonary disease (COPD), characterized by clinical sub-phenotypes such as emphysema (E) and chronic bronchitis (CB), is associated with a greater risk of lung cancer (LC). This study aimed to assess the expression patterns of circRNA and their potential functional involvement in LC patients with COPD. A circRNA microarray was used to characterize differentially expressed circRNAs (DEcircRNAs) profiles. A total of 176, 240, 163, and 243 DEcircRNAs were identified in comparisons between CB vs. LC patients (Con), E vs. Con, E vs. CB, and CBE vs. Con, respectively. DEcircRNAs in all comparison groups were primarily associated with immune-related GO terms and were also enriched in immune and inflammatory pathways. In total, 49 DEcircRNAs were significantly correlated with the infiltration of multiple immune cells. Among them, hsa-MROH9_0001 and hsa-RP11-35J10_0013 were positively and negatively correlated with plasma cells and T-cell CD4 memory resting cells, respectively; these two DEcircRNA-sponged miRNAs have good diagnostic performance. WGCNA identified six key circRNAs associated with CB progression. The expression patterns of hsa-MROH9_0001 and circRNA_21729 in E and CB groups were confirmed by RT-qPCR. In conclusion, we reported circRNA profiles and the findings demonstrated that hsa-MROH9_0001 and circRNA_21729 may be potential therapeutic targets for LC with COPD.