Background: Esophageal adenocarcinoma (EAC), is characterized as a malignancy with poor 5-year survival rate and a growing incidence in the western countries. Although gastroscopy remains the gold standard for EAC surveillance, it is invasive and suffers from poor sensitivity and high miss rates. Furthermore, there is lack of availability of any serological markers for EAC diagnosis. While growing evidence indicates that miRNAs are promising substrates for noninvasive cancer diagnostics, individual miRNAs appear to have limited clinical usefulness. Recent advancements in whole transcriptomic RNA-Seq approaches have allowed comprehensive miRNA expression profiling - an important requisite for identification and development of novel and robust miRNA biomarkers for various diseases, including EAC.
Aim: Using a systematic and comprehensive miRNA expression profiling in large, multiple, independent patient cohorts, we aimed to develop and validate a circulating miRNA-signature for the early detection of EAC.
Methods: A RNA-Seq dataset (n=102) was used to identify miRNA candidates, which were subsequently validated by qRT-PCR assays in 42 pairs of matched cancer and normal tissues. The robustness of the candidate miRNA biomarkers was assessed in sera from patients with EAC (n=44) and Barrett’s esophagus (BE; n=20), and healthy subjects (n=30). Using a training cohort of EAC patients (n=160), a circulating miRNAsignature was established and its diagnostic performance was subsequently validated in another large independent validation cohort (n=556).
Results: We initially identified a panel of 14 differentially-expressed miRNAs from the tissue RNA-Seq dataset, 11 of which were successfully validated in another cohort of EAC patients. Interestingly, 7 of these miRNAs demonstrated significant upregulation in sera of patients with EAC vs. BE and healthy subjects. Subsequently, in a training cohort, we established a 6-miRNA signature (miR106b, -146a, -15a, -18a, -21, and -93) which could significantly discriminate EAC patients from healthy subjects (AUC: 0.86). The diagnostic performance of this miRNA signature in a large, independent, validation cohort yielded an impressive AUC of 0.89. Intriguingly, our data also revealed that this miRNA signature was able to successfully distinguish patients with premalignant dysplasia from healthy subjects (AUC: 0.84, sensitivity: 80%, specificity: 84%), which is far superior to currently used endoscopic approaches.
Conclusions: Using a comprehensive biomarker discovery and validation approach, in potentially one of the largest cohort of EAC/dysplasia/BE patients analyzed to date (n=996), we have established a novel miRNA signature for the detection of EAC. Our miRNA signature is non-invasive, cost-effective and may serve as a clinically transformative approach for diagnosing patients with esophageal cancer.