Evaluation of Plasma microRNA Expression Levels in Early Diagnosis of Colorectal Cancer

Evaluation of Plasma microRNA Expression Levels in Early Diagnosis of Colorectal Cancer  Background: Colorectal cancer (CRC) is the third most frequently diagnosed cancer all over the world and the prognosis is associated with the stage at diagnosis. Due to insufficient sensitivity of tumor markers, as CEA, CA19.9, guaiac-based fecal occult blood and fecal immunochemical occult blood testing used in the routine, there is a need for non-invasive, new biomarkers with high sensitivity and specificity and they will be helpful in early diagnosis. microRNAs (miRNA) are small, single-stranded noncoding transcripts, and some of them play critical roles in tumorigenesis and have a potentially clinical value in diagnosis, treatment and prognosis evaluation for CRC. In this study we aimed to compare miRNA’s expression profiles between pathologically diagnosed CRC patients and healthy control groups. Methods: Blood samples from participants were collected for test-scale analysis. Plasma samples were extracted from whole blood, then total RNA are isolated and pre-amplified as manufacturer’s protocol. Finally, real-time PCR step was performed with BioMark System by using manufacturer’s protocol. Results: Plasma samples of 37 CRC patients and 238 healthy subjects were examined to profiling 741 miRNAs expression, using high-throughput real-time quantitative RT-PCR. Among them, 3 miRNAs (miR-1274A, miR- 875-5p, miR-34c-5p) were found significantly up-regulated while 8 miRNAs (miR-30d-5p, miR-150-5p, miR-30a-5p, miR-34a-5p, miR-223-3p, miR-576- 3p, miR-30c-5p, miR-195-5p) were found down-regulated in CRC patients compared to control group. Conclusion: In this study it was shown that miR-150-5p, miR-30a-5p, miR- 34a-5p, and miR-195-5p can be helpful in early diagnosis of CRC similar to some other studies.