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66 Cards in this Set
- Front
- Back
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Explain the "natural social contract" between cells.
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Cells within a single organism typically live cooperatively--the only way to survive; following the social contract and respecting…
- Rate of Cell Division - Natural Location of Cells There is normally no competition between cells of a single individual. |
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How do cancerous cells break the "social contract"?
Reference: http://youtu.be/8LhQllh46yI |
Rather than cooperating, the cancer cell begins proliferating and prospering at the expense of the other cells. Additionally, these cancer cells are insensitive to signals that tells them to stop growing. In the end, the whole society collapses, and the organism dies.
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How do cancer cells disregard the social contract of rate of cell division?
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Cancer cells lose normal contact inhibition, and continue to divide despite bumping into other cells.
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How do cancer cells disregard the social contract of natural cell location?
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Cancer cells invade areas reserved for other tissues, and may eventually spread to other tissues via the bloodstream.
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What is a tumor/neoplasm?
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A tumor, also known as a neoplasm, is an abnormal mass of tissue which may be solid or fluid-filled. A tumor does not mean cancer - tumors can be benign (not cancerous), pre-malignant (pre-cancerous), or malignant (cancerous).
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What does a cancer cell look like? What are the warning signs?
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1. Hyperplasia – overgrowth of normal looking cells.
2. Atypia – Abnormal looking cells. 3. Dysplasia – “Bad formation” of cells; an abnormal expansion of immature looking cells (cancer cells are often less fully differentiated than normal cells). 4. Carcinoma in situ – Neoplastic cells that have not spread. Tissues look more dense than normal; can be considered as the start of “Cancer Stage”. 5. Ductal Cancer - Cancer cells have spread/invaded surrounding tissue. |
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Explain the difference between a benign and malignant tumor.
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Benign - tumor remains clustered around a single mass, surrounded by a fibrous capsule, and do NOT invade surrounding tissues.
Malignant - tumor is considered cancerous because it is able to invade surrounding tissue. Here the tumor is able to break loose and form secondary tumors (METASTASES). The more metastases that occur, the more difficult it is to completely rid the body of the cancer. |
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Do benign tumors still cause health concerns?
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Yes.
- They can compress adjacent tissues, interfering with their function. This is particularly problematic in the brain. - Tumors of endocrine cells can cause release of excessive levels of hormone |
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List and describe the FOUR main risk factors for cancer.
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1. AGE: Increase of Age = Increase accumulation of mutations over time.
2. GENETICS: Approximately 5% of cancers are strongly hereditary, involving inheritance of a gene that confers a high risk of developing one or more specific types of cancer. 3. ENVIRONMENTAL EXPOSURES: Environmental carcinogens cause genetic changes that are not inherited (known as somatic mutations). Chemicals, tobacco, dietary factors, sunlight, hormones, radiation exposure, etc., all contribute. 4. LIFESTYLE: Changes in behavior can prevent many cases of cancer. - Smoking accounts for about 30% of cancer deaths, and 80% of deaths due to lung cancer. - Overweight and obesity contribute to and another 14% to 20% of cancer-related mortality. - Other are related to infectious agents, such as hepatitis B virus, human papilloma virus, and human immunodeficiency virus, and helobacter pylori, controllable by behavioral changes or antibiotics. - Skin cancers can be prevented by avoiding sun exposure and use of sunscreen. |
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Why would your risk of cancer increase as your age increases? Based on this explanation, explain why young children have cancerous cells.
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You see that most cancer cases are found in older generations. This can be explained by understanding that the individual has MORE TIME to get exposures = MORE TIME to accumulate exposure = MORE TIME for mutation to develop.
Cancer Cases in YOUNG Children = LESS TIME to get exposure and LESS TIME to accumulate exposures, therefore the presence of cancer can mostly be explained by mutation disorders/genetic issue that was present at the fetus stage. |
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Is it reasonable to compare prevalence of cancer to mortality rates of cancer?
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NO.
Example: - Lung Cancer is almost always fatal and accounts for 30% of cancer deaths. - Incidence of Prostate Cancer is considerable higher than lung cancer but it accounts for just about 9% of cancer deaths in men. |
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Why is devising treatment for cancer so difficult?
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Cancer is not a single disease. Cancers originated from different types of cells and act very differently.
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CANCER IS NOT A SINGLE DISEASE.
________ is the most comment type of cancer and it is derived from epithelial tissue. |
CARCINOMA.
- 90% of all cancers. - Most cell proliferation occurs in the epithelial tissue; growth not as tightly controlled as elsewhere. - These cells line the surface of the body and body cavities, they are more likely to be exposed to carcinogens or to physical damage, which is key to the development of cancer. - Includes most breast, cervical, lung, prostate and colon cancers. |
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CANCER IS NOT A SINGLE DISEASE.
________ is another type of tumor of epithelial cells, in which the tumor forms a gland or a gland-like structure. |
ADENOMA.
- Usually benign. - Tend to compress rather than infiltrate surrounding tissue. - Examples: Adrenal tumors and thyroid tumors. |
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CANCER IS NOT A SINGLE DISEASE.
________ originates in connective tissue and muscle. |
SARCOMA.
- Relatively rare. - Found in bone, muscle, and other soft tissues. |
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CANCER IS NOT A SINGLE DISEASE.
________ derived from stem cells of the blood. |
LEUKEMIA.
- Far less common that carcinoma but NOT rare. - Again dealing with cells that divide often. - Far more curable than most other cancers. |
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CANCER IS NOT A SINGLE DISEASE.
________ is cancer of the plasma cells. |
MULTIPLE MYELOMA.
- Most common in older people. - Cancerous plasma cells proliferate rapidly, and move into the bone marrow, where they cause lesions, making the bone increasingly fragile. - The production and release of huge quantities of antibody increases plasma protein levels, which can cause damage to the kidney. - patients also become immunosuppressed as a result of immune dysfunction. |
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CANCER IS NOT A SINGLE DISEASE.
________ is cancer of the lymphocytes. |
LYMPHOMA.
- They can occur anywhere in the body that lymphatic cells are found, including lymph nodes, the spleen, the liver, etc. - Hodgkin’s lymphoma is characterized by the presence of abnormal lymphocytes called Reed-Sternberg cells. It has a bimodal age distribution, peaking in young adults (age 15-35), and again after age 55. It also occurs in children. Often curable – 90% recover, but the radiation therapy used to treat the disease substantially increases the risk of other cancers later in life (especially breast cancer), particularly if the person was treated for Hodgkin’s disease at a young age. - Non-Hodgkin’s lymphomas typically originate in B cells, or (rarely) in T cells. It is more common, but less curable. |
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CANCER IS NOT A SINGLE DISEASE.
________ is a tumor in the brain, generally benign, but can compress brain structures causing seizures and problems with sensation and motor control. |
MENINGIOMA.
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CANCER IS NOT A SINGLE DISEASE.
________ is a tumor in the brain originating from glial cells; invasive and commonly malignant. |
GLIOMA.
- Most malignant brain tumors. - Cancer of the glial cells (cells that support the neurons). - Known for developing branches and grows from site to site. Often times wrapping around blood vessels. - Neurons themselves rarely become cancerous – this makes sense, as these cells rarely divide. |
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CANCER IS NOT A SINGLE DISEASE.
________ is a tumor in the brain originating from blood vessels; generally disappears as a child grows. |
HEMANGIOMA.
- Generally harmless malformation of blood vessels seen in infants, usually disappears during childhood. |
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How do normal cells become cancer cells?
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- Genetic mutations that cause them to grow out of control.
- Cell must undergo about 3-7 independent random genetic changes; exposure to certain types of carcinogens can result in genomic instability. |
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What are the two ways to alter cell proliferation?
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1. Oncogene Formation; in their normal form (proto-oncogene), these genes promote normal cell division. When mutated (forming an oncogene) they cause excessive cell division.
2. Tumor Supressor Genes; these genes normally suppress cell division, keeping the cell from dividing too rapidly. Many are also involved in DNA proofreading. When damaged, this control is lost and cell division proceeds inaccurately and too rapidly. |
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What key mutations increases the likelihood of additional mutations?
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- The most important are mutations in genes that are involved in the “proofreading” of the DNA; include adenomatous polyposis coli (APC) and p53 genes.
- These lead to genomic instability, and make subsequent mutations more likely. |
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Explain what occurs when oncogenes become activated.
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Oncogene is a gene that, when mutated or dysregulated, participates in the onset and development of cancer. (Normal form is called a “proto-oncogene”).
When activated the protein may be… - Expressed at a greater level (more protein in the cell) - Become more active. - Lose its potential to be regulated. - Increase its stability (hang around in the cell longer) These changes can cause the cell to be hyper-responsive to growth signals, grow in the absence of proper growth signals, evade apoptosis, etc. |
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Explain what occurs when tumor suppressor genes stop working.
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A tumor suppressor gene is a gene that protects a cell from one step in the cancer pathogenesis process. The gene product may be a protein that maintains the normal cell cycle, inhibits an oncogene, inhibits cell division, etc.
When a tumor suppressor gene is mutated or dysregulated, the cell can progress to cancer if other aberrations are also present. |
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In regards to the cell cycle, how do cancer cells and normal cells differ?
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Normal cells have a certain number of divisions while cancer cells can divide indefinitely.
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What can cause genetic mutations to occur?
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Infectious agents—Viruses.
Chemical carcinogens—Chemical Adducts to DNA. Radiation—chromosome breaks and translocations. |
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How do viruses alter cell growth and promote the development of cancer?
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DNA Viruses: The virus manipulates the host cell to maximize its replication by activating DNA replication and then uses host machinery to make copies of viral DNA. If the virus becomes a stable part of the host’s genome, it can act as an oncogene to cause excessive cellular proliferation.
RNA Retroviruses: - When a retrovirus infects a cell, its RNA is copied into DNA and inserted into the host’s genome. It is then carried through subsequent generations of cells. The host cell is often stimulated by the virus to divide, causing DYSREGULATION OF THE CELL DIVISION PROCESS. - Occasionally, the retrovirus picks up an oncogene from the previous host cell and carries it to the next host; transforming retrovirus. - A retrovirus can also facilitate the conversion of a proto-oncogene into an oncogene; slow-acting retrovirus. |
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How do chemical carcinogens alter cell growth and promote the development of cancer?
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Chemical agents induce chemical changes in DNA.
- Chemical agents might covalently bing to DNA, creating a DNA adduct. - Chemical carcinogens may cause changes to RNA and proteins, which influence the regulation of proliferation; epigenetic changes. - Increase of DNA replication and cell division can also be a direct result of exposure to chemical carcinogens. |
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How does radiation alter cell growth and promote the development of cancer?
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- Causes chromosome breaks and translocations.
- Interferes with DNA repair. - Radiation used to treat one form of cancer can trigger another cancer later in life. |
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Tumor cells become malignant when they gain the ability to break out of their localized tissue and enter the blood stream (spreading). How does cancer spread from one site to another?
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1. Tumor cells must first loosen their adherence to their neighboring cells, and breakthrough the basal lamina and the underlying connective tissue.
2. Tumor cells can then enter the bloodstream via lymphatic system or angiogenesis. |
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Explain how tumors cells can enter the bloodstream via the lymphatic system.
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Once tumor cells break out of their localized tissue they typically cross the wall of a a lymphatic vessel, and, as the lymph is dumped into veins near the heart, they are able to enter the circulation. Along the way, tumor cells often become trapped in lymph nodes, giving rise to lymph node metastases.
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How does ANGIOGENESIS assist the spread of cancer cells?
Reference: http://youtu.be/8LhQllh46yI |
Angiogenesis is the development and growth of capillaries.
Tumors can induce the formation of their own vasculature through angiogenesis, allowing cancer cells from the interior of the tumor to easily cross the wall of these newly formed blood vessels, and enter the bloodstream directly. |
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What happens once cancer cells enter the bloodstream?
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Cancer cells can become lodged in organ capillary beds, and establish a new tumor (metastases).
1. The site of the metastasis is often just downstream from the original tumor. - Metastases from the colon often occur in the liver, since the hepatic portal vein, which drains the intestines leads to the liver. - The lungs are a common site for metastases, since all the blood from the heart passes through the lungs. 2. After becoming trapped by in organ capillary beds, the cancer cell then escapes from the capillary by extravasation, and invades the new organ site. - The first step in this process is the adherence of the cancer cell to the endothelial cells that make up the capillary. Once the cancer cell adheres, the endothelial cells retract, making it easier for the cancer cell to pass through (thus the endothelial cells actually facilitate the invasion). - Next, the cancer cell must penetrate the basement membrane that underlies the endothelial cells. This requires enzymes that dissolve the material that makes up the membrane. - The final step is the movement of the pseudopodia (“false foot”) through across the capillary wall, and into the new site of metastasis. |
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How does the immune system respond to cancer cells?
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- Cytotoxic T cells are the cells that are most concerned with destroying cancer cells.
- They recognize cells of the body (based on their MHC I) and recognize foreign or abnormal antigens that are typically present on the surface of a tumor cell. - Fewer than 1 in 10,000 tumor cells that enter the bloodstream will survive to produce a tumor at a new site. |
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What are some strategies for cancer treatments?
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1. Chemotherapy
2. Radiation 3. Anti-Angiogenic Factors 4. Targeted Therapies (Examples: Hormonal therapy -block hormones that promote tumor growth. Monoclonal antibodies – target markers on the tumor with antibodies, immune system destroys them.) 5. Surgery |
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Why does cancer therapy sometimes fail?
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- Once cancer cells have left the primary tumor and has spread, it becomes extremely difficult to attack the all these “secondary” tumors.
- Additionally, treatments are restrictive. Radiation – tissue damage. Chemotherapy – treatment is restricted by exposure limits. |
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Explain how each cancer treatment fights cancer cells.
- Chemotherapy - Radiation - Anti-angiogenic Factors - Hormonal therapy - Monoclonal antibodies |
- Chemotherapy; specifically kill fast-growing cells.
- Radiation; cause further genetic mutations such that the cancer cells cannot survive. - Anti-angiogenic Factors; hurt blood supply to nutrient hungry cancer cells and slows growth. - Hormonal therapy; block hormones that promote tumor growth. - Monoclonal antibodies; target markers on the tumor with antibodies, immune system destroys them. |
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How is surgery used for cancer?
Reference: http://www.cancer.org/treatment/treatmentsandsideeffects/treatmenttypes/surgery/surgery-how-is-surgery-used-for-cancer |
Surgery can be done for many reasons, here are a few examples:
- Preventative Surgery; remove body tissue that is likely to become cancer. - Diagnostic Surgery/Biopsy; taking out a piece of tissue and testing it to find out if cancer is present and what type of cancer it is. - Staging Surgery; find out how much cancer there is and how far it has spread. - Curative Surgery; usually done when cancer is found in only one area or region of the body, and it’s likely that all of the cancer can be removed. |
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What are some side effects of chemotherapy and radiation?
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Chemotherapy and radiation can also kill other normal rapidly dividing cells, causing severe toxic side effects.
- The lining of GI tract is injured, causing ulcers and digestive problems. - Bone marrow, the source of new blood cells, is also damaged; leads to anemia. - Patients can become immunocompromised, since these treatments also damage the stem cells that give rise to immune cells. - Over time, tumors may become resistant to a given chemotherapeutic agent, and a different agent must be used to continue to control the growth of the tumors. |
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How do people die of cancer?
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- Compression of healthy tissues, especially in the brain.
- Organ failure, as tumor compromises function of the organ of origin, or an organ where it has metastasized. (Example: Liver Failure) - Infection; chemotherapy compromises immune system. (Example: Pneumonia) |
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When does cancer become painful?
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- Cancer spreads to the bones.
- Toward the end of life, people with cancer often experience difficulty breathing, and are given extra oxygen. - Organ failure; liver metastasis in someone with breast cancer can cause liver failure, which causes discomfort. |
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State TWO examples of cancers of the female reproductive system.
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1. Breast Cancer
2. Cervical Cancer |
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True of False:
Breast Cancer is the most common reproductive cancer and can even occur in men. |
TRUE.
- Worldwide incidence for breast cancer has generally risen since 1940. - Most common in industrialized countries. - Can occur in men; men account for about 1% of breast cancer cases. |
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What are some signs and symptoms of breast cancer?
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- Tumors are usually detectable by mammogram before they can be felt by the patient.
- Physical signs include breast lump, thickening, swelling, distortion, tenderness, and changes in nipple shape and texture. |
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Conditions associated with _____ levels and ____ duration of estrogen exposure increase risk of breast cancer.
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Conditions associated with HIGH levels and LONG duration of estrogen exposure increase risk of breast cancer.
RISK FACTORS: - Nulliparity (never having borne or nursed a child), or first pregnancy after age 30. - Early menarche (< age 12) and late menopause (> age 50); high levels of estrogen. - Prolonged estrogen therapy (10-20 years) seems to increase risk. - Use of older forms of birth control pills (high estrogen dose). - Obesity after menopause (fat cells can produce estrogen). - Alcohol use (alcohol can increase estrogen production). |
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Risk of breast cancer _________ with age.
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INCREASES.
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Vigorous physical activity and maintenance of a healthy body weight are associated with _____ risk of breast cancer.
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LOWER.
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Can genetics play a role in the development of breast cancer?
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YES. Breast cancer susceptibility genes are thought to be responsible for 5 – 10% of all breast cancers (primarily in younger women).
The most studied breast cancer genes are BRCA1 and BRCA2. These genes are also associated with ovarian cancer. - BRCA1 and BRCA2 are tumor suppressor genes. When functioning normally, they regulate the process of cell division. - Each person inherits two copies of each of their autosomal genes. However, a person who has inherited a mutated form of either of these breast cancer genes from one parent will have only one functioning copy of the gene from the start. This means that if the second copy is damaged, it can very easily give rise to cancer. |
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How is estrogen believed to increase risk of breast cancer?
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- Estrogen promotes growth of breast tissue. When ever there is growth, there is increased risk of cancer.
- When there is damage to the genetic material, or to the machinery associated with cell division, a signal that triggers cell division can cause abnormal excessive growth, giving rise to a tumor. - Completing a full term pregnancy is thought to lower the risk of breast cancer by causing breast cells to become fully differentiated. In the fully differentiated state, they are less susceptible to the growth-promoting effects of estrogen. |
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How do hormonal therapy aid in the treatment of certain breast cancers?
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Hormone Therapy (typically TAMOXIFEN, if the tumor has estrogen or progesterone receptors):
- Typically TAMOXIFEN, if the tumor has estrogen or progesterone receptors is used as an estrogen antagonist. - Aromatase inhibitors block estrogen production. (Aromatase is the enzyme that synthesizes estrogen) |
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How do targeted monoclonal antibody therapy aid in the treatment of certain breast cancers?
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Human Epidermal Growth Factor 2 Positive (HER2-Positive) cancer cells are particularly aggressive. They account for about 25% of breast tumors.
- Herceptin is a monoclonal antibody that targets HER2- Positive cells. It targets these cells for destruction by the immune system. - Herceptin also impedes the replication of HER2-Positive cells. |
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What are the stages of breast cancer?
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Stage 0—Carcinoma in situ
5 year survival = 100% Atypical cells have not spread outside of the ducts or lobules. Stage I—Early stage invasive breast cancer 5 year survival = 99% The tumor is < 2 cm in diameter, and has not spread to surrounding lymph nodes or outside the breast. Stage II A and B 5 year survival = 92 and 81% Tumor enlarging, beginning to spread to local lymph nodes Stage III A and B 5 year survival = 67 and 54% Further enlargement, and spread to additional lymph nodes or the chest wall and other local structures. Stage IV 5 year survival = 23% The cancer has spread to distant organs or tissues, such as the liver, lungs, brain, or bone. |
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What is the leading cause of mutations involved in cervical cancer?
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Human Papilloma Virus (HPV).
The virus causes mutations by integrating their DNA into the host DNA. |
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What are some signs and symptoms of cervical cancer?
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- Abnormal vaginal bleeding or spotting.
- Abnormal vaginal discharge. - Pain and systemic symptoms occur at late stages. |
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How can cervical cancer be detected early?
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- Pap screening, in which a sample of cervical cells is examined microscopically for signs of dysplasia (abnormal shape or growth) detects abnormalities before cells become cancerous.
- Women who are sexually active or who have reached the age of 18 should have annual pap smears. After three years of normal results, the physician may allow the smears to be repeated less often. |
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What are risk factors of HPV?
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- Sexual Behaviors; women who have sex at an early age, who have multiple partners or who have partners who have multiple partners are at high risk.
- Cigarette smoking increases risk. |
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How can cervical cancer be treated?
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For PRE-INVASIVE lesions, the cells may be destroyed by cryotherapy (destroying cells by extreme cold), or by electrocoagulation (destruction by extreme heat), laser ablation, or local surgery.
INVASIVE CANCERS are treated by surgery or radiation, or both. In some cases, chemotherapy is used. |
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What are the 5 year survival rates for each stage of cervical cancer?
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- Survival for patients with pre-invasive lesions is nearly 100%.
- The 5 year survival rate for all stages is 83%. - The 5 year survival rate for localized cervical cancer is 95%. In white women, 56% of cervical tumors are diagnosed at this stage, and among black women, 44% are diagnosed at this stage. |
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State TWO examples of cancers of the male reproductive system.
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1. Testicular Cancer
2. Prostate Cancer |
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What are the risk factors of testicular cancer and how is it treated?
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Causes are unknown, but risk factors include:
- Congenital malformations of the testes, collectively known as testicular dysgenesis syndrome (TDS), which includes undescended testes, or failure of the testes to develop properly. - Incidence is gradually rising, and there is concern that exposure to natural estrogen or to endocrine disruptors either in utero or during childhood could increase risk. Treatment generally requires removal of the affected testis. |
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What is the most common cancer of the male reproductive system?
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PROSTATE CANCER is the most common cancer in men, striking about 186,320 each year, and killing 28,660. One in six men will be diagnosed with prostate cancer in their lifetime, and 1 in 36 will die from it.
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What are some risk factors of prostate cancer?
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- Dietary fat consumption and obesity increases risks.
- STDs may increase risks. - Frequent ejaculations, especially in younger men appears to reduce the risk of developing prostate cancer later in life. - Frequent flushing of the reproductive tract may clear out carcinogens. |
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How can prostate cancer be treated?
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Treatment options typically include surgery and/or radiation, and, if the tumor has spread beyond the testes, hormonal therapy, which involves suppressing testosterone levels.
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What is PSA? Why is it used to screen for prostate cancer? Are there any problems associated with using it as a biomarker of cancer?
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- Prostate Specific Antigen; associated with prostate growth.
- Widespread PSA testing has lead to an increase in diagnosis. - Unable to distinguish between indolent cases, which will probably never progress, and more aggressive ones. - Recent government recommendations discourage testing in healthy men. |
