Differential Expression of miR-20a and miR-145 in Colorectal Tumors as Potential Location-specific miRNAs.

Background: MicroRNAs (miRNAs), as tissue specific regulators of gene transcription, may be served as biomarkers for Colorectal Cancer (CRC).

Objective: This study aimed to investigate the potential role of the cancer-related hsa-miRNAs as biomarkers in Colon Cancer (CC) and Rectal Cancer (RC).

Methods: A total of 148 CRC samples (74 rectum and 74 colon) and 74 adjacent normal tissues were collected to examine the differential expression of selected ten hsa-miRNAs using quantitative Reverse Transcriptase PCR (qRT-PCR).

Results: The significantly elevated levels of miR-21, miR-133b, miR-18a, miR-20a, and miR-135b, and decreased levels of miR-34a, miR-200c, miR-145, and let-7g were detected in colorectal tumors compared to the healthy tissues (P<0.05). Hsa-miR-20a was significantly overexpressed in rectum compared to colon (p =0.028) from a cut-off value of 3.15 with a sensitivity of 66% and a specificity of 60% and an AUC value of 0.962. Also, hsa-miR-145 was significantly overexpressed in colon compared to the rectum (p =0.02) from a cut-off value of 3.9 with a sensitivity of 55% and a specificity of 61% and an AUC value of 0.91.

Conclusion: In conclusion, hsa-miR-20a and hsa-miR-145, as potential tissue-specific biomarkers for distinguishing RC and CC, improve realizing the molecular differences between these local tumors.