Genes involved in cell cycle activity/survival are mutated to contribute to the development of cancer. Name the two categories of genes related to cell division that are mutated and how mutations...

BIOL 304, Section 3681
Name: ___________________
Biology of Cancer
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Short Answer: Please be concise with your answers and as specific as possible.
1.
Genes involved in cell cycle activity/survival are mutated to contribute to the development of cancer. Name the two categories of genes related to cell division that are mutated and how mutations affect their function and lead to cancer.
Ans. The categories of gene that are involved are proto-oncogenes and tumor suppressor genes.
The mutation in proto-oncogenes, that have importance in signal transduction pathways, cause them to have gain of function due to which they become Oncogenes, thus causing individual or cell type specific uncontrolled proliferation and finally cancer.
The mutation in tumor suppressor genes, like p53, which keep a check at DNA damage level and involved in apoptotic pathway, cause a faulty functional gene product and thus faulty gene regulation which in turn causes defective cell growth.
2.
How do changes in endothelial and immune cell function contribute to cancer?
Ans. Endothelial cells are the cells responsible for the formation of blood vessels, lymph nodes etc. These cells have a rare species of cells which are known as Endothelial Progenitor Cells, which have the ability to differentiate into endothelial cells and are thus involved in the process of vasculogenesis. Any mutation or change in function of these causes faulty blood vessels or alterations in the cell growth system, thus resulting in cancer.
Cells of immune system are for long known to be involved in the process of combating cancer. T-lymphocytes, B-lymphocytes cells of immune system help the body system to recognize any foreign or alien particulate within the system and thus help and eliminate the same. A faulty immune cell response, due to mutation will result in the system having altered cells thus not able to fight the unwanted agents which can further lead to alterations at genetic levels, resulting in unregulated gene regulation and finally cancer.
3.
Name two carcinogens and how each contributes to a specific type of cancer. Include information on how they act as carcinogens.
Ans. Asbestos, a known carcinogen causes Mesothelioma cancer, which is the only asbestos-related cancer almost exclusively caused by asbestos. It results when an individual ingests or inhales asbestos for prolonged time span. The inhalation or ingestion causes the pleura (lining of the lungs) and peritoneum (abdominal cavity lining) to inflammate as well as direct DNA damage. If prolonged, this inflammation and DNA damage from asbestos exposure may finally lead to formation of tumors.
Benzene causes Leukemia, benzene is activated in the liver to phenolic metabolites and then transported to the bone marrow where they are coverted to semiquinone radicals and quinones via peroxidase enzymes (active oxygen rich species) consequently causing DNA strand breakage, mitotic recombination, chromosome translocations, and aneuploidy. These changes further take up the form of tumors.
4.
Humans are diploid organisms. What does this mean, and how does this help prevent cancer when a gene is mutated? Provide an example in your response.
Ans. By diploid, the meaning is that humans are born with pair of genes, so we are diploid organisms. Cancer, at genetic level impacts a gene. It is very possible that it does so with only one half of the pair. Moreover, it is widely known, for cancer to occur, it has to be in the dominant state where wither it should be present on the dominant gene or the human should be homozygous for the gene, i.e, it should have both genes of pair affected. When...