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Cancer Immunology Essay

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Cancer immunology
Our immune system protects our bodies from pathogens like bacteria and viruses very efficiently in most cases. One big question that has come up is why does the immune system not respond to cancerous cells in the same way? Why are cancer cells not eradicated like other dangerous foreign cells? This seems very strange, especially since the immune system has cells that are specific to destroying cancer cells and virus-infected cells, called natural killer cells. To begin to answer this question it is useful to examine cancer cells and their interactions with the immune system in more detail.
Tumors are formed by the alteration of the body’s own cells. This can be caused by environmental factors such as radiation, like UV exposure, chemicals or viruses 1. These can disrupt genes that control growth and cause an increase in cell division and proliferation. Proto-oncogenes are those genes that control normal but essential cell processes that keep cell growth and death in check. Two important categories are apoptosis genes, which regulate cell death, and tumor suppressor genes, which decrease cell propagation 1 . If these genes were mutated to the point where they cannot produce a functioning protein, cell division would continue far past what it was supposed to and unhealthy cells would be allowed to live and continue to multiply. This is what creates a malignant tumor. Certain conditions in the body can also promote the growth of cancer cells. One of these is a deficiency of natural killer (NK) cells, which are able to kill cancer cells by creating a pore in the cell membrane with perforin and releasing granzymes into the cell. Low levels of perforin allow for tumor growth 1. Chronic inflammation can also ...

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...gens are exogenous (outside the cell) and will be presented to helper T cells to initiate an immune response. This can trigger cytotoxic T cells to kill cancer cells with the same antigen – often HPV viral proteins in cervical cancer. T cells may not be activated to their full potential – recall that the inhibitory receptor CTLA-4 on T cells sends a stronger signal than CD28, the activating receptor. Ipilimumab is added to treatment for this reason. It will work in conjunction with the released antigens, activating the T cells that can respond to the antigens and create an immune response against the cancer cells (LACC article). Adding ipilimumab to the chemo/radiation treatment would enhance the immune system’s ability to respond to the antigen released by the treatment. This is the first time a treatment like this has been suggested for cervical cancer (LACC).
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