Circulating miRNAs as non-invasive biomarkers for non-small cell lung cancer diagnosis, prognosis and prediction of treatment response.

The discovery of a new class of molecules, the 22-24 nucleotides long RNA, has initiated a new chapter in genetic information regulation studies. These molecules have a significant impact on the functioning of cells by means of negative regulation of expression of targeted mRNA. Special attention is given to exogenous, circulating miRNAs, whose levels of expression in different body fluids varies and can be deregulated by pathological, as well as physiological conditions. Extensive studies on the diagnostic potential of miRNAs are currently conducted. Attempts are made to determine specific profiles of miRNAs that will correlate with disease entity. The preliminary data gives hope that in the near future miRNAs will be applied as a diagnostic and prognostic biomarkers in many diseases. One of their most significant applications can be in the diagnosis of lung cancer - the most deadly form of cancer, due to its too late diagnosis. Abundant in miRNA molecules, blood and sputum constitute excellent diagnostic material for patients with lung cancer, especially those with non-small-cell lung cancer NSCLC. Easy procedures for obtaining this diagnostic material from patients and relatively easy analysis of miRNA expression, make these molecules promising in their use in diagnosis, predicting of therapy effects and prognosis for patients with NSCLC. This work presents information related to miRNA and their specific attributes. Moreover level of deregulated circulating miRNAs occurring in body fluids of patients with NSCLC is also discussed.