evaluation of radiotherapy on mir-374 gene expression in colorectal cancer patient blood samples

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-374 expression, and apc and gsk-3β, 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 25 patients before and after radiotherapy. rna was extracted from the blood and cdna synthesized. mir-374, apc, and gsk-3β 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-374 (0.63-fold) and upregulation of apc (1.12-fold) and gsk-3β (1.22-fold) in crc patients after five weeks of radiotherapy. sequencing of pcr-produced amplicons confirmed the conservation of mature and precursor sequences encoding mir-374. mir-374 expression changed with time after radiotherapy treatment and related tumor grading. increased age and tumor grade positively correlated with decreased mir-374 expression. conclusions: mir-374 expression, and that of its two target genes, apc and gsk-3β, changed after radiotherapy. these genes can likely be used as diagnostic radiotherapy markers in crc.