Sputum MicroRNA Profiling: A Novel Approach for the Early Detection of Non-Small Cell Lung Cancer

Abstract

Purpose: MicroRNAs (miRNAs) post-transcriptionally regulate hundreds of gene targets involved in tumorigenesis thereby controlling vital biological processes, including cellular proliferation, di erentiation and apoptosis. MiRNA pro ling is an emerging tool for the potential early detection of a variety of malignancies. is study was conducyed to assess the feasibility and methodological robustness of quantifying sputum miRNAs, employing quantitative real-time polymerase chain reaction (RT-qPCR) and cluster analysis on an optimized miRNA pro le as a novel approach for the early detection of non-small cell lung cancer (NSCLC).Methods: e relative expressions of 11 miRNAs in sputum (miR-21, miR-145, miR-155, miR-205, miR-210, miR-92, miR-17-5p, miR-143, miR-182, miR-372, and let-7a) in addition to U6 were retrospectively assessed in four NSCLC-positive and four negative controls. Subsequently, a set of ve miRNAs (miR-21, miR-143, miR-155, miR-210, miR-372) was selected because of degree of relatedness observed in the cluster analysis and tested in the same sputum sample set. e ve optimized miRNAs accurately clustered these eight retrospective patients into NSCLC positive cases and negative controls. e ve miRNA panel was then prospectively quanti ed in the sputum of 30 study patients (24 NSCLC cases and six negative controls) in a double-blind fashion to validate a ve miRNA panel using hierarchical cluster analysis.Results: e optimized ve miRNA panel detected NSCLC (83.3% sensitivity and 100% speci city) in 30 prospectively accrued study patients.Conclusion: Sputum miRNA pro ling using cluster analysis is a promising approach for the early detection of non-small cell lung cancer. Further investigation using this approach is warranted.

MicroRNA Expression Profiling of Sputum for the Detection of Early and Locally Advanced Non-Small-Cell Lung Cancer: A Prospective Case–Control Study

“…The normalized sputum expression profiles for each individual (the 3-mirna panel) were evaluated using hierarchical cluster analysis as validated in our previous work 21 . Cluster analysis is a statistical method that groups similar (or related) objects within a group ("cluster"), thereby placing dissimilar objects in other groups 28 ; it is useful for analyzing complex biologic data.…”

“…Based on our previous experience, we did not evaluate sputum cytology as a surrogate marker for sputum adequacy 21 . Sputum cytology is associated with a high rate of false positives for the detection of nsclc 25 .…”

“…Xie et al 16 demonstrated a significant difference in sensitivity when they compared sputum cytology with mirna expression. Total rna isolation, rna reverse transcription, and rt-qpcr, which were conducted according to the manufacturer's recommendations, are described in our previous study 21 . The procedure is briefly summarized in the subsections that follow.…”

“…A post-hoc analysis revealed that 3 mirnas (mir-21, mir-210, mir-372) were primarily responsible for the diagnostic power of the panel. Individually, those 3 mirnas have been used in nsclc blood and sputum evaluations because of their overexpression, as documented in our own experience and in the literature 21,22 . This specific 3-mirna panel has not previously been reported in the literature.…”

“…Our previous work used single sputum samples from 24 prospectively accrued patients of all nsclc stages and from 6 healthy control subjects to evaluate a 5-mirna panel (mir-21, mir-143, mir-155, mir-210, mir-372) for the detection of nsclc, demonstrating 83.3% sensitivity and 100% specificity 21 . A post-hoc analysis revealed that 3 mirnas (mir-21, mir-210, mir-372) were primarily responsible for the diagnostic power of the panel.…”