Association of lncRNA MEG3 Rs7158663 Polymorphism and Serum Expression with Colorectal Cancer in Egyptian Patients.

Background: Colorectal cancer (CRC) is considered the third most common cancer around the world and second in terms of mortality. A significant aspect in its development is genetics. The risk of CRC and other clinicopathologic characteristics were investigated in this work in relation to the long non-coding RNA (lncRNA) MEG3 rs7158663 polymorphism, MEG3 expression, in an Egyptian population. Methods: 160 CRC patients and 160 healthy controls were enrolled in this case-control study. The lncRNA MEG3 rs7158663 was examined using TaqMan Real-time PCR. RT-PCR was used to assess the levels of serum MEG3 expression. Results: A significant higher expression of 'A' allele (risk allele) and A/A genotype in CRC cases vs. control subjects (P <0.001) Participants with A/A genotype had 4.8 times higher odds to exhibit CRC. Serum MEG3 gene expression was generally low in CRC patients, and it was considerably lower in those with the rs7158663 AA genotype than those with the GG genotype (P <0.001). It was found that CRC patients with the rs7158663 GA genotype had lower serum MEG3 expression levels than those with the GG genotype (P <0.001). Conclusions: MEG3 low expression and MEG3 rs7158663 (AA) were associated with CRC risk in Egyptian patients and may serve as a diagnostic and prognostic marker for CRC patients.