module 3 review questions

Question 1

Describe the two processes that must occur in order for normal renewal and repair to take place.

Answer 1

Cell proliferation: an increase in the number of cells as a result of cell growth and cell division

Cell differentiation: cells acquiring the characteristics of the tissue that they make up

Question 2

Describe benign tumours (4 points). How are they generally named?

Answer 2

Growth is usually slow and may come to a stop

Made of fairly well-differentiated cells and well-organized stroma (connective tissue framework)

Do not invade beyond their capsule

No metastasis

Generally named for the tissues from which they arise, with the suffix “oma”

Question 3

Can benign tumours still cause problems? How?

Answer 3

Can still be a problem if the growth interferes with function of surrounding tissue or inappropriately produces hormones

Question 4

Describe malignant tumours (4 points).

Answer 4

More rapid growth rate

Loss of differentiation (anaplasia) and tissue organization (a spectrum from low to high grade) cells are pleomorphic (different sizes and shapes)

Lack a capsule and invade nearby blood vessels, lymphatics and surrounding structures

Most deadly characteristics: the ability to metastasize (spread far beyond the tissue of origin)

Question 5

How are malignant tumours generally named?

Answer 5

Named for cell type from which they originate with “carcinoma” (epithelial tissue) or “sarcoma” (from mesenchymal tissue (connective, bone muscle))

Question 6

What does “adeno-” at the beginning of a name mean?

Answer 6

From glandular tissue

Question 7

Define lymphoma and leukemia.

Answer 7

Lymphomas: from lymphatic tissue

Leukemias: cancers of blood forming cells

Question 8

Describe the two categories of malignant neoplasms.

Answer 8

Solid: initially confined to specific tissue/organs tumours

Hematologic: cells normally found in blood/lymph tumours

Question 9

From what tissue type are most human cancers derived?

Answer 9

Transformation of epithelial cells

Question 10

Describe “carcinoma in situ”. Where can this occur?

Answer 10

Refers to a growth with malignant characteristics (increased proliferation rate and atypical cells) in epithelial tissue that has not (yet) invaded local tissue

Occur in breast, cervix, skin, stomach

Question 11

Describe eight cancer cell characteristics.

Answer 11

Genetic instability: there is a high frequency of mutations in cancer cells

The cell must become independent of external growth signals: able to make their own, don’t need any, extremely sensitive to growth factors so will respond to extremely low levels

Loss of contact inhibition (normal cells usually stop growing when they come into contact with each other)

Decrease in cell adhesion (normal cells have membrane structures that allow them to stick together – cancer cells have less of these and can then more easily be shed from a tumour, increasing the possibility of metastasis)

Loss of anchorage dependence – normal epithelial cells will ide if they are not attached to another cell, or to an underlying extracellular matrix. Cancer cells can survive and grow under conditions that normal cells can’t

Production of unusual antigens (cell surface markers that are identified as foreign by the immune system), enzymes, or hormones that are not made by the tissue of origin

Able to divide without limit – telomeres are sections on the end of each chromosome that get shorter with each division. Cancer cells have a very active enzyme called telomerase, that can lengthen telomeres. Therefore, they can divide without a limit

Altered metabolism, increasing anaerobic respiration

Question 12

What is metastasis?

Answer 12

The spread of cancer cells from the original site to distant organs and tissues

Question 13

Describe the difference in the local growth of benign vs malignant tumours.

Answer 13

Benign: pushes on surrounding connective tissue that eventually forms a capsule around the growth

Malignant: helped by enzymes made by the cancer cells that break down cells and connective tissue of surroundings. Growth is by sending “crablike” extensions into surrounding tissue

Question 14

Identify the difference in the route of spread of growth between carcinomas vs sarcomas.

Answer 14

Carcinoma: epithelial tissue derived, spread through lymph

Sarcomas: fibrous tissue derived, spread through blood

Question 15

What is a “sentinel node”?

Answer 15

If the spread is through the lymph, the tumour cells lodge first in the initial lymph node that drains that area

Question 16

Describe six possible local effects of a tumour.

Answer 16

Compression: e.g. brain tumour: headaches, nausea, loss of consciousness, death

Obstruction: e.g. blockage to airways

Infarction: growth of mass can obstruct blood vessels, causing local necrosis of tissues

Hemorrhage: damage to blood vessels

Rupture

Effusions: inappropriate amounts of fluid

Question 17

Describe nine systemic effects of cancer, including how the cancer and/or the treatment can be the cause of the problem. (Review: what is the term for manifestations of a disease that are caused by medical treatment?)

Answer 17

Paraneoplastic: symptoms triggered by a cancer, but not caused by direct local effects of the tumour mass

Pain: little to none in early stages, can be strong in later stages. Can result from pressure, stretching, inflammation

Fatigue: not relieved by sleep or rest. May be due to sleep disturbances, various biochemical changes

Cachexia: loss of body mass due to metabolic disturbances caused by a disease and cannot be reversed nutritionally

Anemia: caused by chronic bleeding, malnutrition, chemo

Leukopenia and thrombocytopenia: caused by tumour invasion of bone marrow, chemo, radiation

Infection: due to loss of immune cells due to reasons above

GI tract: relies on rapidly multiplying tissue which is the type of tissue affected by chemo and radiation

Hair and skin: also due to rapidly growing tissue being affected by therapeutic agents

Question 18

What is the multistep theory of carcinogenesis?

Answer 18

Beginning: mutation that makes one cell more likely to divide (hyperplasia)

One of the descendant cells experiences another mutation that causes its descendants to look abnormal (dysplasia)

Yet another mutation eventually occurs in a further descendant cell which results in very abnormal structure, loss of differentiation, and loss of contact inhibition between the cells; however, they are still confined to the epithelial layer from which the original cell arose (carcinoma in situ)

Additional mutations may occur that enable them to invade neighbouring tissues and shed cells into the blood or lymph (malignant)

The escaped cells may establish new tumours at other locations in the body (metastasis)

Question 19

What is the effect of age on the development of cancer (why is cancer more prevalent with age)?

Answer 19

It requires several mutations to produce a malignant tumour, the older a person is, the greater the chance that these mutations have occurred

Question 20

Why is the alteration of tumour suppressing genes said to be recessive in effect?

Answer 20

These are usually the type of genes that are involved in cancer that can be inherited (individuals can inherit a defective allele, but have the protection of another allele. However if the other allele becomes inactivated, then a tumour can develop)

Question 21

Describe and give an example for two other factors that could contribute to the development of cancer.

Answer 21

Changes in the control mechanisms that govern which genes are expressed

Changes in metabolic pathways inside the cell (e.g. loss of DNA repair machinery that could fix an oncogene)

Question 22

Be familiar with the causative factors of cancer, including: a. Inflammation b. Viral and bacterial infections c. Environmental/lifestyle interactions d. Heredity e. Immunological mechanisms f. Age g. Chemical carcinogens h. Low strength (solar) radiation and high strength (nuclear) radiation

Answer 22

Chronic inflammation has been recognized for close to 150 years as being an important factor in the development of cancer & inflammation and cancer both involve the migration of neutrophils, lymphocytes and macrophages, with the release of factors that stimulate the growth of cells and blood vessels. Inflammatory cells also release compounds that can promote mutations

Viral: a number of viruses have been associated with cancer, through alteration of the DNA that the virus may cause, or through inflammation caused by the viral disease:

80% liver cancer associated with chronic hepatitis caused by HBV & HCV

All cervical cancer caused by HPV

EBV virus infects B cells and stimulates growth

Bacterial chronic infection with helicobacter pylori has been linked to gastric carcinoma

Environmental: cigarette smoking, excessive alcohol consumption, poor diet, obesity, lack of exercise, exposure to UV

Question 23

Describe the stages of carcinogenesis.

Answer 23

Initiation: Exposure to carcinogenic agent, Irreversible mutations to genome, May be many small doses over time, Cells in mitosis or meiosis

Promotion: Cytokines and growth factors begin to induce cell proliferation

Progression: Tumour cells eventually acquire all the characteristics needed to invade and metastasize to other tissues

Question 24

Differentiate between CT, MRI and PET scans.

Answer 24

CT – can see larger areas than with one x-ray and can check for metastasis

MRI – provides more soft tissue detail than CT, but more expensive and time-consuming

PET – like CT, but uses a biologically active molecule attached to a tracer, to show metabolically active tissue

Question 25

Describe the 4 stage system of classifying cancer.

Answer 25

Stage 1: confined to origin

Stage 2: local invasive

Stage 3: spread to local lymph nodes

Stage 4: spread to distant sites

Question 26

Describe WHO’s TNM system.

Answer 26

TNM: tumour size (t) lymph node involvement (n) extent of metastasis (m)

Question 27

Name the 3 main treatments for cancer and describe the basis on which they work.

Answer 27

Chemotherapy: targets metabolic pathways – hopefully a cancer cell is more sensitive to a particular chemical.

radiation therapy: targeted cells die through molecular damage caused by ionizing radiation

surgery

Question 28

Why are chemotherapeutic agents often given as “cocktails”?

Answer 28

Usually in combinations, to decrease the amount given of any one drug and increasing attack on cancer cells (some cells in a tumour may be resistant to one drug, but susceptible to another one in the cocktail given)

Question 29

What is brachytherapy?

Answer 29

Can be through an external beam, or by placing
small radioactive capsules in the affected area
(brachytherapy) – e.g., cervical, prostate, head and
neck cancers.

Question 30

Describe induction, adjuvant and neoadjuvant chemotherapies.

Answer 30

– Can be given alone (induction), or in combination with
surgery (either after (adjuvant), to eliminate small
metastasized tumours, or before (neoadjuvant), to
minimize removal of normal tissue)

Question 31

What are three uses for surgery other than complete removal of the tumour?

Answer 31

May be used prophylactically (women with BRCA1/2
mutations)
– Obtaining tissue for biopsies (if surgery is being used for
diagnosis)
– Establishing staging information by observing and sampling
local lymph tissue