Tremendous efforts have been made to develop
cancer biomarkers by detecting circulating extracellular
miRNAs directly released from
tumors. Yet, none of the cell-free
biomarkers has been accepted to be used for early detection of
non-small cell lung cancer (NSCLC). Peripheral blood mononucleated cells (PBMCs) act as the first line of defense against
malignancy in immune system, their dysfunction may occur as an early event in
cancer immunogenicity or immune evasion. We proposed to investigate whether analysis of
miRNA expressions of PBMCs has diagnostic value for NSCLC. We first used a microarray to analyze PBMCs of 16 stage I NSCLC patients and 16
cancer-free smokers, and identified seven PBMC
miRNAs with a significantly altered expression level in NSCLC patients. In a training set of 84 NSCLC patients and 69
cancer-free smokers, a panel of two
miRNAs (miRs-19b-3p and -29b-3p) were developed from the seven PBMC
miRNAs, producing 72.62% sensitivity and 82.61% specificity in identifying NSCLC. Furthermore, the
miRNAs could identify squamous cell lung
carcinoma (SCC), a major type of NSCLC, with 80.00% sensitivity and 89.86% specificity. The expression levels of the
miRNAs were independent of disease stage. In a testing set of 56 NSCLC patients and 46 controls, the performance of the
biomarkers was reproducibly confirmed. The study presents the first in-depth analysis of PBMC
miRNA profile of NSCLC patients. The assessment of PBMC
miRNAs may provide a new diagnostic approach for the early detection of NSCLC.