Bio Chapter 11

Some viruses have been linked to particular cancers.

(DONT MEMORIZE) Several forms of human papilloma virus (HPV) are the most common causes of cervical cancer. Epstein-Barr virus (EBV) has been linked to both Hodgkin's and non-Hodgkin's lymphoma. The hepatitis B and C viruses are linked to liver cancer. HIV/AIDS is linked to non-Hodgkin's lymphoma and Kaposi's sarcoma. The human T-cell leukemia/lymphoma virus is linked to T-cell non-Hodgkin's lymphoma.

New methods usually use one of three refined techniques for controlling cancer:

-Attacking the tumor cells with specifically designed or selected immune cells or antibodies. -Crippling the proteins that promote the cancer. -Cutting off the blood supply to the tumor.

Risk factors for breast cancer:

-Being a woman (male breast cancer is rare) Age --1 in 200 women will develop breast cancer before age 40. --1 in 26 will develop breast cancer before she reaches her 60s. -Early menarche (the first menstrual cycle). -Late menopause. -Obesity -Use of hormonal contraceptives such as birth control pills or patches. -Hormone replacement therapy after menopause.

Brain Cancer

-Brain cancers are infrequent but are usually fatal after a short time. --A primary cancer does not usually form in the brain. --Brain cancer is usually a sign of metastatic disease that has spread from a primary cancer of the breast, colon, or lung. -It is very difficult to treat brain cancers, since cancerous tissue must be totally separated from healthy tissue in order to maintain the highest possible level of brain functioning.

Radiation therapy can be deadly to dividing cells.

-It does not distinguish between cancer cells and the cells of healthy tissue. -It interrupts cell growth only where the radiation beam is aimed. -Localized effects include hair loss, irritated skin, blistering and burns. -Other systemic effects include dry mouth, fatigue and nausea.

Three of the most common cancers are also three of the most deadly:

-Lung -Colorectal -Breast

Symptoms of Leukemia and when is a definite diagnosis made?

-Symptoms are nonspecific, including fatigue, weight loss, and frequent infections, which are similar to the symptoms of many other diseases. -A definitive diagnosis is made after a blood test and a bone marrow biopsy.

Cancer cells lack differentiation...

-They have no specified function and therefore can make no contribution to the overall functioning of a particular body part. -They have no homeostatic function in the body. -They have abnormal nuclei and chromosomes

Prostate cancer

-occurs in men, most commonly after age 50. -Symptoms include difficulty or inability to urinate, blood in the urine, or pain in the pelvic area. -Treatments include surgical removal of the prostate gland, radiation, and hormonal therapy

Cancer cells have mechanisms that allow them to avoid destruction by the immune system...

-some include mechanisms that actively seek to avoid the body's defenses -Other cancers simply overwhelm the immune system defenses by multiplying more rapidly than they can be killed off.

Tumor-suppressor genes can also mutate...

Altered tumor-suppressor genes will no longer regulate the cell cycle and will not promote apoptosis. Such mutations are referred to as "loss-of function" mutations.

The process by which new blood vessels are formed

Angiogenesis --Once it has a blood supply, the tumor becomes immortal. Unless it is cut out, killed with chemicals, damaged by radiation or another substance, or starved of its nutrient supply, the tumor will grow and spread until it kills its host.

____vitamins counteract the effects of the free radicals that are a normal byproduct of cellular metabolism.

Antioxidant -Free radicals are generally detoxified by the body's natural processes, but if that cleansing is inefficient, they that build up in the body can damage other molecules, including DNA.

Programmed cell death is called ____

Apoptosis -cancer cells manage to avoid it; they become "immortal"

There are three types of skin cancer:

Basal cell carcinoma, squamous cell carcinoma, melanoma

When proto-oncogenes mutate, they form oncogenes, or genes that cause cancer.

Because there are many proto-oncogenes in each cell, it is possible to form many oncogenes in one cell. Oncogenes disrupt cellular function, so the more oncogenes that are activated, the less able the cell will be to support its normal function.

_____ are sometimes performed in conjunction with chemotherapy or high-dose radiation therapy that destroys fast-dividing bone marrow cells.

Bone Marrow transplants

___ can be defined as uncontrolled cell replication that occurs because of a breakdown in the normal mechanisms of cell regulation

Cancer

_____ cells either disregard or don't receive the chemical signals that tell them it is time to stop dividing and die.

Cancer

_____ cells have unlimited potential to replicate.

Cancer -Normal cells are programmed to die if their DNA is damaged or if they replicate too many times.

____ is one of the leading causes of death in the United States; nearly one-third of us will develop __ in our lifetimes.

Cancer, cancer

Many ____ cells have antigens on their surfaces that are not found on normal cells of the body. -Usually, ___ cells recognize these abnormal antigens in potentially cancerous cells and destroy them.

Cancer; T Cells

The two most prevalent forms of environmental carcinogens are __ and __

Chemicals and radiation

____ disrupts cells throughout the body.

Chemotherapy -It uses compounds that specialize in killing fast-growing cells. -Chemotherapy interrupts cell growth throughout the entire body. --Prevents cell division in normal healthy cells as well as cancer cells. --The hope is that the growth of the cancerous tumor will be stopped before the drug causes death of healthy organs.

Lung cancer diagnosis is based on symptoms.

Cigarette smoking is by far the leading factor in the development of lung cancer. Other risk factors include household, workplace, or environmental exposure to chemicals, asbestos, and radiation. There is no screening test for lung cancer; it is diagnosed based on symptoms, which include persistent cough, frequent pneumonia or bronchitis, and changes in the voice.

Obesity has been linked with an increase of 50 percent or more in the incidence of __ cancer among both men and women and to an increase of 50 percent or more in the risk of breast and uterine cancer among women.

Colon

Pregnant women and their fetuses are especially susceptible to some kinds of industrial pollution.

During periods of active cellular growth and differentiation, the fetus can be negatively affected by even minute quantities of introduced carcinogen

Experimental treatments include:

Genetic therapy Magnetism Phototherapy

There is no single cause for an individual cancer. However, many factors play a role in initiating and promoting cancer such as:

Heredity, environment, viruses, diet --Researchers are finding that most cancer causing mutations are the result of the body's cells accidentally damaging their own genes in the normal course of cellular metabolism.

There are two main categories of lymphoma

Hodgkin's disease and non-Hodgkin's lymphoma

The _____ destroys most potentially cancerous cells. --It recognizes these cells as "other" or "nonself" and reacts to them as it would any other foreign tissue, through the process of rejection.

Immune system

____ Is cancer of the white blood cells.

Leukemia

___ is a form of cancer that attacks the lymph nodes.

Lymphoma

Certain foods may have a protective effect against cancer.

Many fruits and vegetables are high in antioxidant vitamins

__ is the process by which the original cancerous tumor spreads throughout the body.

Metastasis

__ is another form of environmental radiation. It is a colorless, odorless gas that is released by water, soil, and rocks in varying amounts and intensities in different geographic areas. -__is thought to be the 2nd leading cause of lung cancer.

Radon; radon

Four ways to make a definitive diagnosis of cancer:

Screening tests Imaging (mammography, X-rays, MRI or CAT scans) Tumor enzyme tests Genetic tests

___ cancer is the most common type of cancer for both men and women.

Skin

Cancer Diagnosis

Some cancers are diagnosed based on a set of symptoms, and others can be detected through routine screening. When diagnosed early, however, all cancers can be treated.

3 standard treatments for cancer:

Surgery Radiation therapy Chemotherapy

Symptoms of lymphoma

Symptoms include intermittent fever, weight loss, and night sweats. -Enlarged lymph nodes are most frequently recognized in the groin, armpits, and neck

If ____ is present in the cell, the telomere is repaired after every division, and the cell can continue to divide indefinitely

Telomerase --The cell that develops the ability to maintain telomerase in its cytoplasm lives "forever" and is on its way to being a cancerous cell.

__ are tiny pieces of DNA located at the tips of chromosomes and are maintained by an enzyme called telomerase.

Telomeres --Each time a cell replicates, a little bit of the telomere is snipped off. A typical cell replicates 50-60 times before the entire telomere is gone. At that point the cell stops replicating, and eventually wears out and dies.

Only about 2 percent of cancer deaths are linked to exposure to industrial pollutants.

The majority of these cancers occur in people who work in an industry that uses the carcinogenic substances and not in people who are exposed to diffuse environmental pollution

Cancer treatment has long focused on killing or removing the primary __, then attacking any metastatic tumors that may be present.

Tumor

Once a ___ has become firmly established in such a "primary site," cancerous cells often break away from the original mass and travel through the bloodstream or lymph.

Tumor -Metastasis is the process by which the original cancerous tumor spreads throughout the body. -Traveling cells are deposited at "secondary sites," where other tumors may develop. -Metastatic tumors may continue to grow even if the primary tumor is killed or removed.

_____ are chemicals produced by the body in response to the development of a tumor.

Tumor markers --When they are present in the blood, they "mark" or indicate the presence of a tumor.

Breast cancer genes 1 and 2, or BRCA1 and BRCA2, are __________

Tumor-suppressor genes

___ can invade almost any body tissue from skin and bone to organs like the lungs, liver, and intestine.

Tumors

Treatment of Lymphoma

Typically, treatment consists of high-dose radiation treatment or chemotherapy, sometimes followed by bone-marrow transplant. Newer treatments, such as specific antibodies to lymphoma cells, have shown promise.

Nuclear fuel, whether used to generate power or to produce bombs, has been linked to __

cancer

Once they have overcome the body's defenses, ___ cells can exploit their advantage and continue to grow and multiply unchecked, carrying many mutations that were all set in motion by a single mutation in a control gene.

cancer --These mutated cells can then successfully outcompete normal cells for space and nourishment. Carcinogenesis has begun.

Radiation is another ___ agent

carcinogenic

Tobacco smoke, for example, contains a number of chemicals that have been identified as __

carcinogens -Even the paper used in cigarettes includes harmful chemicals, which are released when the cigarette is burned. -Estimates of the percentage of cancer deaths linked to cigarette smoke run from 30 percent to 80 percent.

The most common treatment for leukemia is___ to destroy cancerous white cells, often followed by a bone marrow transplant to replace the destroyed cells

chemotherapy

Diets high in animal fat from beef, pork, and dairy foods have also been associated with an increased risk of __ cancer.

colon -Chemicals called nitrites, which are converted into nitrosamines in the digestive process, are often used as a preservative in lunch meats and other foods. -Fish and shellfish that feed in waters contaminated by chemicals or heavy metals often store some of these carcinogenic substances in their flesh.

____ has also been linked to increases in many forms of cancer, especially cancers of the mouth, throat, and esophagus, as well as breast and liver cancers.

excessive alcohol consumption

If the ___ system is weakened, cancerous cells have a distinct advantage.

immune

Our bodies produce cancerous cells each day, but most are killed by our ___

immune system

Nuclear radiation and X-rays are __sources of radiation. While brief and low-level exposures are not dangerous, prolonged or very high-level exposures can cause cancer.

ionizing

Radiation can be: ___ and ___

ionizing and non-ionizing

When a _____ growth reaches about 1 million cells (approximately 1 or 2 millimeters in diameter), the cells in the interior can no longer receive enough nutrients, and they begin depositing their waste products within the cell cluster.

malignant cancerous ---This ball of cells is called a carcinoma in situ ("cancer in place"). It needs its own blood supply. It produces its own growth-enhancing proteins and secreting chemicals called angiogenic compounds that lure blood vessels into the tumor.

Most breast cancer is diagnosed by means of a ___, an X-ray of breast tissue.

mammogram

Cancer is not a single disease...

more than 100 specific diseases are lumped together under the term cancer.

Most colorectal cancers start as benign )___

polyps. -A high-fat, low-fiber diet and a sedentary lifestyle have been linked to increased risk of colon cancer. There is a screening test for colorectal cancer, the colonoscopy. Rectal bleeding or bloody stool, even in a younger person, necessitates a colonoscopy.

_____ is the most prevalent source of non-ionizing radiation

sunlight -Over 80 percent of skin cancers are caused by exposure to higher-frequency ultraviolet B (UVB) rays of sunlight

If a mutated BRCA1 or BRCA2 gene is inherited from either parent, the child carries that mutated gene in every cell in her body. If a second BRCA1 or 2 mutation occurs...

the child's chances of developing cancer increase. -If the second mutation develops in breast tissue cells, the result is breast cancer. -If the mutation develops in an ovary, the result is ovarian cancer.

Growth-stoppers are called ____ ; growth promoters are ____

tumor-suppressor genes; proto-oncogenes -these can suffer random mutations -if both the tumor suppressor genes an proto-oncogenes in the same cell are altered, the result could be cancer.