Chs. 12, 13, 14: Cancer

Which statement concerning a multifactorial cause is true?

A multifactorial cause or multiple causation concept suggests that the interaction of many factors most likely produces cancer.

Leukemia

Cancers of blood-forming cells

Which of the following is the most common solid tumor in children?

Central nervous system (CNS) tumors

It is true that tobacco smoking:

Has been declining among U.S. adults since 1997.

Which viruses are linked to the development of cancer?

Hepatitis B and C, Epstein-Barr virus, Human papillomavirus

What happens with telomeres in cancer cells?

In cancer cells the telomerase gene is "switched on," producing an enzyme that rebuilds the telomeres. Thus the cancer cells continue to divide indefinitely.

What is the staging of tumors?

Involves the size of the tumor, degree to which it has invaded, and the extent to which it has spread: - Stage 1: Cancer is confined to its organ of origin - Stage 2: Locally invasive - Stage 3: Regional structures - Stage 4: Distant sites

Which drug and environmental exposures are linked to the risk of developing childhood cancers?

Ionizing radiation, pesticide exposure, and anabolic adrenergic steroids

Which statement is true concerning the prognosis of childhood cancers?

More than 80% of childhood cancers are cured

When in its normal state, which gene negatively regulates proliferation?

Tumor-suppressor genes.

Which statement is true regarding ultraviolet (UV) light?

UV light causes basal cell carcinoma and squamous cell carcinoma.

Physical activity reduces the risk of which type(s) of cancer?

breast cancer and colon cancer

Where do most childhood cancers originate?

from the mesodermal germ layer and give rise to connective tissue cancer

What is mitosis?

one blood cell divides once to form two identical cells. it is reproduction of somatic (body) cells. each cells has 46 chromosomes (23 pairs). the purpose is for growth and to replace worn out cells.

Obesity results in a higher risk of death from which cancers?

- esophageal - endometrial - colorectal - kidney - breast - pancreatic

What is Ras?

- is a family of genes encoding small GTPases that are involved in cellular signal transduction. - activation of Ras signalling causes cell growth, differentiation and survival. - Ras communicates signals from outside the cell to the nucleus. These signals result in cell growth and division, and their dysregulation can lead to oncogenesis and cancer

Which statement is true concerning the association of adiposity with cancer?

An association between body mass index (BMI) and breast cancer mortality risk exists.

Staging of Cancer

Cancer confined to the organ of origin is stage 1; cancer that is locally invasive is stage 2; cancer that has spread to regional structures, such as lymph nodes, is stage 3; and cancer that has spread to distant sites, such as a liver cancer spreading to the lung or prostate cancer spreading to bone, is stage 4. The prognosis generally worsens with increasing tumor size, lymph node involvement, and metastasis. Benign tumors do not spread to distant regions.

Which statement regarding tumors is true?

Cancer refers to a malignant tumor. The term cancer refers to a malignant tumor with rapid growth, a loss of differentiation, and the absence of normal tissue organization.

A person drinks alcohol in excessive quantities. Which areas are likely to develop cancer related to alcohol consumption?

Cancers of the gastrointestinal system are linked to alcohol: cancer of the oral cavity, larynx, pharynx, hypopharynx, esophagus, and liver.

Which statement is true regarding the staging of cancer?

Cancers that have spread regionally are stage 3.

A man has worked with asbestos in his career for longer than 40 years. Which cancer is he most likely to develop?

Lung

Which statements are true regarding melanoma?

Melanomas can appear suddenly without warning or can arise from or near a mole (melanocytic nevus) and melanomas most commonly affect whites. Established risk factors for melanoma are genetic and phenotypic traits, increasing age, fair skin and hair color, greater than 20 nevi, freckling, three or more atypical nevi, and an increased likelihood of burning with sun exposure. Environmental exposures important in melanoma include a history of three or more episodes of sunburn; periodic excessive sunlight exposure (vacations with intense exposure); and UV exposure at tanning salons. When detected in the early stages, melanoma is highly curable. Approximately 20% of melanomas, however, are diagnosed at nonlocalized and advanced stages.

What is the term for cancers originating in connective tissue?

Sarcoma

Which statement is NOT true regarding the body's defense mechanisms against cell damage?

The two systems are xenobiotic and antioxidant. The body has two primary defense systems to protect against xenobiotics that cause cell damage: (1) detoxification enzymes, and (2) the antioxidant system.

What is paracrine signaling?

a form of cell-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior or differentiation of nearby cells.

Which statements are true regarding caretaker genes?

- Caretaker genes encode proteins that repair damaged deoxyribonucleic acid (DNA). - Loss of function results in increased mutation rates. - Loss of function can cause increase rates of specific cancers

Which of the following are characteristics of cachexia?

- early satiety - anorexia - weight loss - anemia - asthenia - taste alterations - altered metabolism Clinical manifestations cancer include cachexia.

What is the term for cancers originating in epithelial tissue?

Carcinoma

Which marker is used to evaluate a tumor of the adrenal gland?

Catecholamines Catecholamines are secreted by the adrenal medulla and are found in excess if a tumor exists.

Which virus has been linked with the development of cancer?

Epstein-Barr Epstein-Barr has been linked with the development of Burkitt lymphoma, nasopharyngeal carcinoma, and Hodgkin disease.

Which statement is true regarding childhood cancer?

Leukemia is the most common malignancy in children, and the most common type of leukemia is acute lymphoblastic leukemia (ALL), which represents approximately 75% of all pediatric leukemia cases.

Which of the following is associated with defects of the p53 tumor-suppressor gene?

Li-Fraumeni syndrome (LFS) LFS is an autosomal dominant disorder involving the p53 tumor-suppressor gene that significantly increases the risk of developing cancer as a child or an adult. LFS often has a familial history.

What is the term for cancers originating in lymphatic tissues?

Lymphomas

Which statement is true regarding metastasis?

Metastasis occurs through the vascular and lymphatic systems.

Air pollution is associated with cancer. Which statements pertaining to this association are true?

Ozone is the main ingredient in smog air pollution. Radon is a natural radioactive substance ubiquitous in rock and soil that can be trapped in houses and underground mines. Its radioactive decay products are carcinogenic. Indoor pollution is considered worse than outdoor pollution, partly because of cigarette smoke.

What are the degrees of differentiation for tumors?

good to worse 1. Well Differentiated - closely resembles tissue of origin and retains some specialized functions 2. Moderately Differentiated - less resemblance 3. Poorly Differentiated - does not closely resemble 4. Very Poorly Differentiated - has no resemblance to tissue of origin

What happens during the mitotic phase of the cell cycle?

the cell divides its copied DNA and cytoplasm to make two new cells. it involves two processes: mitosis and cytokinesis

What is meiosis?

the form of cell devision that creates sperm and egg cells. cells have 23 chromosomes

What does the suffix -oma stand for?

tumor - Epithelial tissue = Carcinoma - Connective Tissue =Sarcoma - Glandular = Adenoma - CNS tissue = Glioma - Lymphatic tissue = Lymphoma - Bone Marrow = Leukemia

What are the phases of interphase phase of the cell cycle?

interphase: time period when the cell grows, carries out its metabolic activities, and replicates its DNA in preparation for cell division. resting phase b/c cell is not actively dividing 1. G1 (Growth/Gap) Phase: prior to the start of DNA synthesis. Lively internal growth, heightened metabolic activity, rapid synthesis of RNA and proteins. specialized functions are developed. its the longest phase. 2. S (Synthesis) Phase: DNA is synthesized in the cell's nucleus 3. G2 (Growth/Gap) Phase: RNA and protein synthesis occurs. mitotic spindle develops. begins to reorganize content in preparation of mitosis.

What are telomeres?

protective caps on each chromosome and are held in place by the enzyme telomerase. they become smaller and short with each division until the cells stop dividing

What is metastasis?

the spread of cancer from a primary site of origin to a distant site. steps: 1. Direct or continuous extension 2. Penetration into lymphatics, blood vessels, or body cavities 3. Transport into lymph or blood 4. Transport to secondary sites 5. Entry and growth in secondary sites common sites: lungs liver, bones, brain

What are the types of mutated genes?

1. Secretion of growth factors (autocrine stimulation) - Increased growth factor receptors - Signal from cell-surface receptor is mutated in the "on" position 2. Mutation in the ras intracellular signaling protein 3. Mutation/inactivation of tumor suppressor genes - p53 gene - tumor suppressor gene on chromosome 17

Which of the following is a characteristic of a malignant tumor?

It is able to spread far from the tissue of origin. Malignant tumors have no capsule, which allows them to spread readily. They have rapid growth rates and specific microscopic alterations. They are poorly differentiated and spread to distant tissues.

Which statement characterizes radiation therapy?

Radiation is used to kill cancer cells while minimizing damage to normal structures Effective cell killing using radiation also requires good local delivery of oxygen. Radiation produces slow changes in most cancers and irreversible changes in normal tissues as well.

Describe Autocrine stimulation/signaling:

- is a form of cell signaling in which a cell secretes a hormone or chemical messenger (called the autocrine agent) that binds to autocrine receptors on that same cell leading to changes in that cell - one approach used by tumors to upregulate growth and survival is through autocrine production of growth and survival factors. - autocrine signaling plays critical roles in cancer activation and also in providing self-sustaining growth signals to tumors.

Which statement is true regarding basal cell carcinoma (BCC)?

BCC is most commonly found on sun-exposed areas of the body.

What is the G0 phase?

cells that aren't reproducing and exit the cell cycle enter this phase: - Temporarily during adverse conditions such as a nutritional deficiency, chemotherapy/radiation therapy, or related to mutations that needs to be repaired - Cells may die in G0 or reenter the cell cycle once adverse conditions are corrected - Some damaged cells may not be repaired and give rise to a pool of cancerous cells that hide in G0 and escape chemotherapy drugs * this phase helps us understand cancer treatment protocols with rounds of treatment

Embryonic tumors

contain immature cells and are not well differentiated, which means that they are unable to mature or differentiate into fully developed functional cells. They are diagnosed early in life and often contain the words, blast cell, in their names because of the immature nature of the cells.