The potential use of miRNAs in the diagnosis and prediction of metastatic lung carcinoma.

Lung carcinoma is the "top killer" of all malignancies in the world. Early diagnosis of lung carcinoma significantly improves patient survival. Screening with biomarkers from peripheral blood could detect more patients at an early stage of the disease. MicroRNAs (miRNAs) could be a possible biomarker. These are 21-23 nucleotide long single-stranded RNA molecules playing an important role in the post-transcriptional regulation of gene activity. Individual miRNAs have the potential to regulate genes responsible for cell proliferation, differentiation, apoptosis, regulate cell cycle in cooperation with pro-oncogenes and tumor suppressor genes. In our study, we determined miRNA expression levels in individual samples of lung carcinoma patients and in a healthy control group. We used the reverse transcription method followed by qRT-PCR. The expression levels of the investigated miRNAs were evaluated in the QIAGEN GeneGlobe Data center software. We demonstrated the significance of miR-126 and let-7g as biomarkers of lung carcinoma in all clinical stages studied. We also observed significantly increased expression of miR-143 and miR-145 at the distant metastasis stage, and significantly decreased expression of miR-133a in the N2 disease group of lung carcinoma patients (N2 disease represents disease with metastases in the ipsilateral mediastinal and/or subcarinal lymph nodes or node). The investigated miRNAs showed no clear potential for detecting potentially resectable (N0-N1), locally advanced (N2) and distant organ metastatic (M1) lung carcinoma.