Individual Assignment 3: 10 Discoveries in the War on Cancer
1. Scientists have always dissected lymph nodes nearby a cancerous tumor to see if the cancer has begun to spread to other areas of the body. The most obvious nearby lymph node is chosen. Scientists have discovered that in women with breast cancers that are 5 cm in diameter or smaller, nothing is gained by additional lymph node dissections in the axillary region (armpit) of the body. Dissecting the node nearest the tumor provides adequate information by itself.
2. Malignant brain tumors in adults are fast-growing cancers with median survival rates of 15 months, even with aggressive treatment. Researchers have been searching for genetic “signatures” (characteristic groups of cancer-causing genes) that could help in defining the kind of brain tumor the patient has. They hope to be better able to predict the course of the disease and the patient’s response to treatment.
3. Molecular geneticists have surveyed the entire human gene collection (the “genome”) in patients with neuroblastoma , a childhood cancer that forms in the adrenal glands and nerve tissue. Results of a genome-wide association study indicate that a specific region on human chromosome 1 is associated with the development of this cancer. This chromosome region contains a section of DNA that can vary in copy number from person to person, and neuroblastoma patients were more likely than control subjects to have fewer than normal copies of this DNA.
4. Tobacco smoking is the leading cause of preventable deaths worldwide. It is a risk factor for lung cancer and several other types of cancer. Results of analysis of the entire human gene collection (the “genome”) support some previous findings that a region of human chromosome number 15 contains one or more genes that are associated with smoking intensity (the number of cigarettes smoked per day) and the closely related trait of nicotine dependency.
5. Molecular biologists have developed a new sequence of human genes called an ankyrin insulator sequence. You place a new corrected or therapeutic gene within this sequence. Its role is to create an active area on a human chromosome where the new gene can work efficiently no matter what chromosome it lands on.
6. Molecular biologists have taken nanoparticle -sized spheres and used them to deliver a cell-killing toxin from bee venom to tumors in mice, substantially reducing tumor growth without harming normal body tissues. Nanoparticles are known to concentrate in solid tumors because blood vessels in tumors show “enhanced permeability and retention effect” or EPR. Hence, substances such as nanoparticles escape more readily from the bloodstream into tumors, and the generally poor drainage of lymph from tumors further helps trap the particles in tumor tissue.
7. Organic chemists are exploring structural variations of the organic compound avobenzone (1-(4-Methoxyphenyl)-3-(4-tert-butylphenyl) propane-1,3-dione) for inclusion in sunblock products. Avobenzone is known for its ability to absorb a broad spectrum of ultra-violet radiations including UVb light (known to enhance the frequency of basal cell and squamous cell carcinomas (skin cancers)) and UVa rays thought to increase the frequency of melanoma cancers. New variations in the structure of avobenzone are hoped to retain the ability to absorb harmful UV radiation while having an increased stability in the presence of that radiation.
8. Immunologists are investigating ways to destroy lymphocytes (white blood cells of the immune system) that have become cancerous (lymphomas). A current drug Rituxamab contains antibodies that bind to the surfaces of these lymphocytes, setting them up for destruction by the cancer patient’s own immune system. They are currently seeking ways to modify the antibody’s structure so that it will attract the cancer patient’s “natural killer” (NK) cells to the lymphocytes. Success of this project will bring a multi-faceted immune response against lymphomas and hasten its destruction.
9. Biochemists are analyzing the many, many components of red meat (beef, pork) to determine which component, if any, will cause increased colorectal cancer rates in mice when the component is administered orally. Studies have shown that higher colorectal cancer rates in humans are associated with higher consumption rates of red meat.
10. Virologists are modifying lentiviruses as vectors for carrying proto-oncogenes into cancer-transformed cells in culture. They are developing this virus for inserting the ras proto-oncogene directly into its correct location in the genome. The correct ras gene will already be linked to human DNA to either side of it and complexed with a recombination enzyme that will insert it into its correct location within the human genome. At the same time, the recombination enzyme will excise the defective oncogenic form of ras. The cells in culture should again come under normal hormonal control and require extra-cellular signals in order to continue dividing.
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