Mona Elhelaly Elsherbeny - Medical Biochemistry and Molecular Biology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
Alyaa Ramadan Elsergany - Internal Medicine Department, Medical oncology unit, Oncology Center, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
Olfat Gamil Shaker - ۳: Medical Biochemistry and Molecular Biology Department, Faculty of Medicine, Cairo University, Cairo, Egypt.

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) MEG۳ rs۷۱۵۸۶۶۳ polymorphism, MEG۳ expression, in an Egyptian population. Methods: ۱۶۰ CRC patients and ۱۶۰ healthy controls were enrolled in this case-control study. The lncRNA MEG۳ rs۷۱۵۸۶۶۳ was examined using TaqMan Real-time PCR. RT-PCR was used to assess the levels of serum MEG۳ expression. Results: A significant higher expression of ‘A’ allele (risk allele) and A/A genotype in CRC cases vs. control subjects (P <۰.۰۰۱) Participants with A/A genotype had ۴.۸ times higher odds to exhibit CRC. Serum MEG۳ gene expression was generally low in CRC patients, and it was considerably lower in those with the rs۷۱۵۸۶۶۳ AA genotype than those with the GG genotype (P <۰.۰۰۱). It was found that CRC patients with the rs۷۱۵۸۶۶۳ GA genotype had lower serum MEG۳ expression levels than those with the GG genotype (P <۰.۰۰۱).  Conclusions: MEG۳ low expression and MEG۳ rs۷۱۵۸۶۶۳ (AA) were associated with CRC risk in Egyptian patients and may serve as a diagnostic and prognostic marker for CRC patients.

Colorectal cancer, MEG۳, lncRNA, Polymorphism, Rs۷۱۵۸۶۶۳.