Differential diagnosis of non-small cell lung carcinoma by circulating microRNA

More than 70% of lung cancer comprises nonsmall-cell lung carcinoma and is associated with poor survival outcome owing to late diagnosis. Identification of lung cancer in early stages when no clinical signs or symptoms are evident, can drastically improve the prognosis. To this end, we aimed to evaluate the changes occurring at tissue level by assessing the expression of six microRNAs (miRNAs) in lung adenocarcinoma (AC) and squamous cell carcinoma (SCC).

Peripheral blood of histopathologically proven cases of lung AC and SCC was collected and processed for the isolation of miRNAs using commercially available kit. Primers against mir-2114, mir-2115, mir-2116, mir-2117, mir-449c, and mir-548q with loading control Caenorhabditis elegans were used. Screening was carried out in thirty cases of both AC and SCC, whereas twenty healthy controls were included.

Real-time polymerase chain reaction data revealed that the expression of mir-2114 and mir-449c in AC and mir-2115 in SCC was significantly upregulated. The expression of these miRNAs was also confirmed in lung AC cell line. The differential pattern of expression of these miRNAs can be used for precise diagnosis of lung carcinoma.

We have used a noninvasive technique to identify the subtype of lung cancer based on molecular genetic signatures. The results suggest that through molecular profiling of miRNA, we can screen high-risk cases for cancer interception.