Circular RNA profiling identified as a biomarker for predicting the efficacy of Gefitinib therapy for non-small cell lung cancer.

Background: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have become important treatment options for non-small cell lung cancer (NSCLC) patients with EGFR sensitive mutation. However, the detection of EGFR driver mutation is impeded by the lack of adequate tumor tissues, histopathological type, long detection period, and the heterogeneity of a tumor. Therefore, it is necessary to develop a more convenient method to guide the clinical use of EGFR-TKI. Circular RNAs (circRNAs) are characterized as a closed structure with covalently joined ends resistant to exonucleases may be a potential biomarker. In the present study, we aimed to screen circRNAs that may be associated with the efficacy of EGFR-TKI.

Methods: The expression of circRNAs sequenced by circular microarray in plasma samples between gefitinib effective and ineffective groups were compared. RT-qPCR further validated the results in an independent cohort. Kaplan-Meier curves were used to analyze the association between circRNA and progression-free survival (PFS) of NSCLC patients treated with gefitinib.

Results: In total, 52 NSCLC patients treated with gefitinib were included for analysis. 1,377 circRNAs were differentially expressed in gefitinib effective and ineffective groups, among which 989 circRNAs were up-regulated, and 388 circRNAs were down-regulated in the effective group. Furthermore, two differentially expressed circRNAs, hsa_circ_0109320 and hsa_circ_0134501, were validated by RT-qPCR in an independent cohort of 38 gefitinib-treated NSCLC patients. Elevated hsa_circ_0109320 was associated with longer PFS in gefitinib-treated NSCLC patients.

Conclusions: Taken together, hsa_circ_0109320 may be a potential biomarker for the efficacy of EGFR-TKI in NSCLC patients. This provides a new molecular typing method for individualized precision treatment.