Background: Colorectal cancer (CRC) is the third most common cancer
worldwide and the third leading cause of cancer-related death. It is a heterogeneous
disease that develops through different genetic and epigenetic mechanisms. To date, no
comprehensive systematic review investigating genetic risk factors for familial and
sporadic CRC has been performed on the extended MENA (eMENA) region.
Aims: This study aimed to systematically analyze genetic variations significantly
associated with CRC in the eMENA region.
Methods: We searched four literature databases (PubMed, Scopus, Science Direct, and
Web of Science) from the time of inception until May 2019 using broad search terms to
obtain all reported genetic data related to eMENA patients with CRC. Variants with an
OR>1 that are associated with CRC were identified.
Results: A total of 1,200 studies were obtained from our search method, 27 of which
met the inclusion criteria for our systematic review, with a total of 8,230 CRC patients
and 7,611 controls. Of these, 1,941 patients distributed throughout nine eMENA
countries were found to carry 46 variants in 33 different genes. Interestingly, 19 variants
were unique to CRC patients in the eMENA region.
Interpretation: This is the first systematic review to capture the spectrum of variants
significantly associated with CRC in the eMENA region. There appears to be a
distinctive clinical picture for eMENA patients with CRC, and the range and distribution
of variants among patients from the eMENA region differ from those noted in other