P53, also known as tumor protein or TP53 is a gene that codes for a protein that regulates the cell cycle, hence functioning as a tumor suppressor. It is also highly targeted by bacteria. Upon mutations of a p53 allele an individual becomes susceptible to cancer. Being the second leading cause of death globally, there were approximately 14 million new cases of cancer recorded in 2012, of which an estimated one million were stomach cancer.
A leading cause of stomach cancer happens to be the Helicobacter Pylori infection, where the bacteria H. Pylori is responsible for causing mutations within the p53 gene resulting in tumors and gastric cancer. It has been noticed that patients with p53 germ-line mutations are not at an increased risk for gastric cancers while they have a tendency to show a high rate of other tumors. This research was undertaken in order to determine whether a p53 germ-line mutation affects their ability to be targeted by bacteria. This can then be used to deduce that a p53 germ-line mutation loses it ability to be targeted by bacteria, and hence reduce risk towards bacteria induced cancers whilst increasing risks towards other types of cancer.
A germline mutation is any detectable and heritable variation in the lineage of germ cells that develop into sex cells. Individuals with this type of mutations usually have Li-Fraumeni Syndrome (LFS) According to a study conducted by members of the Division of Comparative Medicine (NCBI, 2002), after performing several experiments on two groups of mice for up to 15 months, where one group was subject to a germline allele deletion. Both groups were exposed to H.
Pylori. The results were such the group with the mutation experience other types of cancer but not those caused by H. Pylori.In order to make this research valid X countries were chosen and their p53 germline mutation frequencies were noted and processed from the ALFRED (The Allele Frequency Database). The incidence of bacteria induced cancers was taken from the GLOBOCAN (2012) database available online and the incidence of cancers caused by other mutagens were taken from several databases such as WHO (2012), World Cancer Research Fund, and GLOBOCAN.
Therefore my research question was: Is there a link between p53 germ-line mutations and their ability to be targeted by bacteria? If the hypothesis is correct then we should find a negative correlation between bacteria targeting p53 and p53 germ-line mutations.