Serum inflammatory miRNAs predict radiation esophagitis in patients receiving definitive radiochemotherapy for non-small cell lung cancer.

BACKGROUND AND PURPOSE: MicroRNAs (miRNAs) are small, highly conserved non-coding RNAs that regulate many biological processes. We sought to investigate whether three serum miRNAs related to immunity or inflammation were associated with esophagitis induced by chemoradiation therapy (CRT) for non-small cell lung cancer (NSCLC).

MATERIAL AND METHODS: We measured serum miR-155, miR-221 and miR-21, before and during week 1-2 of CRT for 101 NSCLC patients by real-time PCR. Associations between miRNA and severe radiation-induced esophageal toxicity (RIET) were analyzed by logistic regression.

RESULTS: We found that patients with stage IIIB-IV disease, higher mean esophagus dose or esophageal V50 had higher rates of severe RIET. Furthermore, high levels of miR-155 and miR-221 at week 1-2 of CRT were also risk factors for severe RIET (miR-155: OR=1.53, 95% CI: 1.04-2.25, P=0.03; miR-221: OR=2.07, 95% CI: 1.17-3.64, P=0.012). In addition, the fold change of miR-221 was also predictive of severe RIET (OR=1.18, 95% CI: 1.02-1.37, P=0.026). However, pretreatment miRNAs was not predictive of severe RIET.

CONCLUSIONS: High serum miR-155 and miR-221 during the first 2 weeks of CRT were associated with the development of severe RIET, suggesting that these miRNAs may be useful as an early surrogate for this form of toxicity.