MLH1 - 93G > A and I219V polymorphisms are susceptible to increased risk of sporadic colorectal cancer in a Turkish population

Abstract

Colorectal cancer (CRC) comprises approximately 10% of all cancers and is a major cause of cancer-related morbidity and mortality despite current diagnostic and treatment improvements. DNA damage and altered DNA replication through the deregulation of related genes cause genomic instability in sporadic CRC. DNA repair is very complex; many factors play a role to ensure that the restoration of errors occurs during the transfer of genetic material. MutL homolog 1 (MLH1) is one of the vital DNA repair genes responsible for genomic stability. Together with environmental factors, the genetic background may be associated with CRC development; thus, genetic polymorphisms are considered as risk factors. The present prospective case-control study aimed to determine the association between 93G>A and I219V polymorphisms of MLH1 and CRC susceptibility in a Turkish population. The genotyping of 158 patients and 164 age- and sex-matched controls was performed by polymerase chain reaction-restriction fragment length polymorphism. Two variants, 93G>A and I219V, were associated with an increased risk of CRC. Individuals with A allele of 93G>A had an approximately 2-fold risk (OR: 1.92, 95% CI: 1.22-3.04; p<0.01) and those with G allele of I219V had an approximately 3-fold risk (OR: 2.82, 95% CI: 1.76-4.52; p<0.01) of developing CRC. Our results provide novel information for understanding the influence of MLH1 on CRC risk in the Turkish population; however, further studies with a larger number of participants are required.