Tehran University of Medical Sciences Basic & Clinical Cancer Research 2228-6527 9 4 2018 04 07 13 21 EN Ayda Arab Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran Morteza Karimipoor Department of Molecular Medicine, Biotechnology Research Center, Pasture Institute of Iran, Tehran, Iran Shiva Irani Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran Arda Kiani Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran Sirous Zeinali Department of Molecular Medicine, Biotechnology Research Center, Pasture Institute of Iran, Tehran, Iran Elham Tafsiri Department of Molecular Medicine, Biotechnology Research Center, Pasture Institute of Iran, Tehran, Iran Kambiz Sheikhy Tracheal Diseases Research Center (TDRC), National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran 2017 12 02 2018 01 31 Background: Lung cancer is one of the most common malignant tumors with poor survival, which is usually diagnosed at advanced stages. In recent years, increasing evidence has revealed that circulating miRNAs exhibit great potential in screening and early detection of various types of cancers including lung cancer. miR-21 is one of the most highly expressed members of the microRNA family in many human cancer types. Methods: The authors analyzed miR-21 expression in matched tumor and normal tissues and plasma in 17 patients affected with non-small cell lung cancer. Samples were collected from the NSCLC patients before surgery, radiotherapy or chemotherapy. Expression levels of tissue miR-21 were assessed, using TaqMan RT-PCR assay. Expression levels of plasma miR-21 were assessed, using LNA™ RT microRNA PCR primer set and SYBR green qRT-PCR assay. Results: miR-21 expression was higher in 9 out of 17 patients’ plasma samples. No change in miR-21 expression was observed in 8 plasma samples. In lung tissues, ten patients showed up-regulation of miR-21 and six patients were down-regulated. One patient had no change in miR-21 expression level in tissue samples. The expression level of mir-21 in tissue and plasma was concordant in 6 patients. Conclusion: It seems that the level of miR-21 in plasma samples of NSCLC patients as a marker for screening needs more investigation. https://bccr.tums.ac.ir/index.php/bccrj/article/view/265 https://bccr.tums.ac.ir/index.php/bccrj/article/download/265/04