Genetic Susceptibility Markers of Gastrointestinal Cancer
Gastrointestinal cancer is the most common type of malignant disease with high mortality and the second foremost cause of carcinoma deaths worldwide. The frequency of gastrointestinal cancer strongly depends on ethnical and geographical characteristics. For example, the prevalence of gastrointestinal cancer is significantly high in Japan and Korea, whereas in North America and Europe the occurrence of gastrointestinal cancer is very low. Generally, gastrointestinal cancers are diagnosed in late stages due to the heterogeneous nature. By considering the heterogenicity of gastrointestinal cancer, inhibition is depending on the precise diagnosis of risk factors, the underlying cause of the disease, and the management of risk factors. Therefore, this chapter aimed to review the genetic susceptible marker of gastrointestinal cancer. Molecular studies revealed that the development of GC is from the combined effect of various factors like environment, genetic and epigenetic modifications which play a crucial role in tumorigenesis and cellular immortalization. The molecular epidemiological studies revealed that some regular genetic traits act as a genetic susceptible marker to develop GC known as single nucleotide polymorphisms (SNPs) Single nucleotide polymorphisms (SNPs) are naturally occurring genetic modifications that have a different frequency in the diversified ethnic population. There are many associate studies to analyze the genetic susceptibility of GC. Genome wide association studies are used for the identification of various single nucleotide polymorphism in genetic susceptible markers which are responsible for gastrointestinal cancer. Gene polymorphisms become an attractive biomarker of GC due to their environment dependent alterations. Genetic susceptibility is crucial in molecular events related to the development of gastrointestinal cancers includes mucosal shielding, immune reaction to H. pylori infection, carcinogen detoxification, antioxidant protection, repair of DNA injury, and capability of cell propagation. The use of SNPs as prognostic markers for individual gastrointestinal cancers is very advantageous because of the availability and quality of tumor material. In this chapter, we tried to discuss some of the important genetic polymorphisms which affect gastrointestinal cancer susceptibility and how they influence malignant phenotype. The determination of genes responsible for GC susceptibility will give information for the advancement of novel GC therapeutics by studying the molecular events involved in GC carcinogenesis. This chapter includes single nucleotide polymorphisms in genes such as Cdh1, DNMT3A, PTPRCAP, PSCA, VEGF A, XRCC1, IL 1, HER 2, MUC1, and MUC1.