Azam Ahmadi - Infectious Diseases Research Center (IDRC), Arak University of Medical Sciences, Arak, Iran.
Mohamd Reza Bayatiani - Department of Medical Physics and Radiotherapy, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran.
Fatemeh Seif - Department of Medical Physics and Radiotherapy, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran.
Jamshid Ansari - Department of Medical Physics and Radiotherapy, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran.
Parisa Rashidi - Department of Medical Physics and Radiotherapy, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran.
Mona Moghadasi - Students Research Committee, Arak University of Medical Sciences, Arak, Iran.
Mobarakeh Etemadi - Students Research Committee, Arak University of Medical Sciences, Arak, Iran.

Background: Current cancer treatments include surgery, radiotherapy, chemotherapy, and immunotherapy. Despite these treatments, a main issue in cancer treatment is early detection. microRNAs (miRNAs) can be used as markers to diagnose and treat cancers. This study investigated the effect of radiotherapy on miR-۳۷۴ expression, and APC and GSK-۳β, two of its target genes, in the WNT pathway, in peripheral blood samples from radiotherapy-treated colorectal cancer (CRC) patients. Methods: Peripheral blood was collected from ۲۵ patients before and after radiotherapy. RNA was extracted from the blood and cDNA synthesized. miR-۳۷۴, APC, and GSK-۳β expression was determined by real-time polymerase chain reaction (RT-PCR) and the amplicons were sequenced. Finally, the data were statistically evaluated. Results: Quantitative RT-PCR revealed significant down-regulation of miR-۳۷۴ (۰.۶۳-fold) and upregulation of APC (۱.۱۲-fold) and GSK-۳β (۱.۲۲-fold) in CRC patients after five weeks of radiotherapy. Sequencing of PCR-produced amplicons confirmed the conservation of mature and precursor sequences encoding miR-۳۷۴. miR-۳۷۴ expression changed with time after radiotherapy treatment and related tumor grading. Increased age and tumor grade positively correlated with decreased miR-۳۷۴ expression. Conclusions: miR-۳۷۴ expression, and that of its two target genes, APC and GSK-۳β, changed after radiotherapy. These genes can likely be used as  diagnostic radiotherapy markers in CRC.

Biomarker, Colorectal cancer, Mir-۳۷۴, Radiotherapy.