Cancer is a genetic disease. Cancer cells contain various mutations, which includes SNPs to chromosomal aberrations. Together, these changes are referred to as genome instability. Genetic instability is one of the common characteristics of colorectal cancer. In colorectal cancer three major types of genetic instability have been reported. They are chromosomal translocations, microsatellite instability (MSI), and chromosome instability (CIN). Microsatellite instability occurs due to variations in DNA mismatch repair genes, while chromosomal instability is distinguished by major chromosomal alterations occurring at cell division and usually involves β‐catenin and Adenomatous polyposis coli protein (APC) mutations. This chapter summarizes the major molecular mechanisms leading to genomic and microsatellite instability and tumorigenesis.
Part of the book: Microsatellite Markers
Toll-like receptors (TLRs) play an important role in immune-surveillance and responses towards pathogenic and non-pathogenic microorganisms. They act as innate immune sensors against endogenous and exogenous danger signals by recognizing the pattern recognition molecules (DAMPs and PAMPs) and drive an adaptive immune response through their signaling pathways, which leads to NF-κB and IRF3 transactivation and induces different inflammatory cytokine genes. TLRs polymorphisms were investigated in various cancer types studies. However, precious studies have reported that the Polymorphisms on TLR1-TLR10 cluster have been associated with increased risk of prostate cancer. However, it has known that TLRs genetic variation is associated with increased the susceptibility to gastric cancer. A same synthetically meta- analysis also confirmed the association of TLRs with increased the gastrointestinal cancer but with decreased prostate cancer risk. Our previous studies have demonstrated a strong link between TLRs polymorphisms and colon cancer and breast cancer in Saudi Arabia population. Similar studies were analyzed with Korean patients with papillary thyroid cancer and their clinic-pathologic features in age matched controls by using direct sequencing. The general objective of this chapter was to investigate the role of different TLRs (i.e., TLR2, TLR4, and TLR6) polymorphisms and their association with cancer development.
Part of the book: Genetic Diversity and Disease Susceptibility