Ch. 9 Biology Of Cancer

Front 1

T/F Cells in the human body are members of a cellular society.

Back 1

True.

Front 2

T/F The goal of the cellular society is the survival of the individual cell.

Back 2

False - The goal of the cellular society is the survival of the entire organism, not the individual cell.

Front 3

What is comprised of the cellular mechanisms and genes that control the birth and death of cells

Back 3

Cellular social control

Front 4

T/F The rate of cell birth and cell death is kept in balance in order to maintain organ & tissue mass.

Back 4

True

Front 5

One mechanism that can trigger cells to divide is what?

Back 5

Damage to tissue

Front 6

T/F When damage occurs and repair is needed, non-dividing cells are triggered to divide and undergo differentiation (specialization).

Back 6

True

Front 7

T/F When the repair is complete, the proliferating cells must be “turned on"

Back 7

False - When the repair is complete, the proliferating cells must be “turned off."

Front 8

What kind of factors create a complex system of biologic signals that “turn on” and “turn off” cell growth?

Back 8

Growth factors

Front 9

What is a disease of cell growth and division (proliferation), as well as cell differentiation?

Back 9

Cancer

Front 10

What is caused by mutation of the genes that regulate cell proliferation and differentiation?

Back 10

Cancer

Front 11

What are the three main genetic mechanisms have a role in the development of tumors?

Back 11

1. Mutation resulting in hyperactivity of genes that stimulate growth; These mutated genes are called oncogenes
2. Mutation resulting in loss of activity of genes that inhibit growth
3. Over-expression of genes that prevent apoptosis (normal cell death), allowing continued growth of tumors

Front 12

How do oncogenes or inactivated tumor suppressor genes cause a tumor cell to proliferate indefinitely?

Back 12

Telomerase- maybe…
• One explanation, which is just a part of the answer, involves the enzyme telomerase, which acts on the telomeres
– A telomere is the DNA’s protein “cap”, which is present at the end of each chromosome
– The telomere shrinks each time the cell divides
– When the telomere loses some of its length, the cell dies
• In immortal cancer cells, the enzyme telomerase adds nucleotides back to the telomere
• With a full-length telomere, cells continue to divide and do not die

Front 13

What are indifferentiated cells in adults called?

Back 13

Stem cells

Front 14

Where are most stem cells found in adults?

Back 14

Bone marrow

Front 15

What kind of cell has the following characteristics?:
– Are not terminally differentiated
– Can divide without limits
– However, normally each division generates one daughter cell
and one differentiated daughter cell

Back 15

Stems cells

Front 16

T/F produce a growing tumor, a stem cell fails to produce one non-stem-cell
daughter in each division, thus proliferating and causing imbalance in
cell production versus cell destruction.

Back 16

True

Front 17

T/F Normal cells can not develop into cancer.

Back 17

False - they can.

Front 18

What is the process by which a normal cell becomes a cancer cell?

Back 18

transformation

Front 19

What is the following:
• During differentiation, certain genes (proto-oncogenes) are normally turned off
• Re-activation of these genes can transform a well-differentiated cell to be less differentiated
• Carcinogenic agents can mutate or re-activate these proto-oncogenes to cause cells to become less differentiated
• Cancer is considered to be a disorder of growth and differentiation because neoplasms resemble undifferentiated tissue
• The less the tumor resembles normal tissue, the more undifferentiated (anaplastic) it is

Back 19

transformation

Front 20

What are tumors classified according to?

Back 20

The degree of differentiation, the tissue of origin, cell type, whether its benign or malignant, and its anatomic site

Front 21

What kind of tumor classification is the following: Tumor grading grades differentiation
• It ranges from grade I to Grade IV
• It is the gauge for the degree of malignancy

Back 21

Degree of differentiation

Front 22

What grade cell is well differentiated and has resemblence of its tissue of origin?

Back 22

grade I

Front 23

What grade cell is moderately differentiated?

Back 23

Grade II

Front 24

What grade cell is poorly differentiated?

Back 24

Grade III

Front 25

What grade cell is very poorly differeniated and has no resemblance of its original tissue?

Back 25

Grade IV

Front 26

What kind of tumor classification is the following: – Some tumors retain some normal function so that the tissue of origin can be identified
– Others are so disorganized that the tissue of origin cannot be identified

Back 26

Tissue origin

Front 27

What type of tumor classification is the following: Tumors are named according to the tissues from which they arise with the suffix “oma”.

Back 27

Cell type

Front 28

What type of tumors have the following characteristics: – Well-differentiated, resemble cell of origin
– Remain localized, do not invade surrounding tissue
– Rate of growth is progressive and slow
– Cause pressure on normal tissue
– Name: adenoma, papilloma

Back 28

Benign tumors

Front 29

What type of tumors have the following characteristics: – Lack of differentiation
– Invade surrounding tissue, irregular borders
– Rate of growth is often rapid and erratic
– Destructive to normal tissue
– Name: Carcinoma, sarcoma

Back 29

malignant tumors

Front 30

What type of tumor classification is the following: – Carcinoma in situ: refers to pre-invasive epithelial tumors of glandular or squamous cell
origin that have not broken through the basement membranes of the epithelium
• Squamous cell origin: cervix, skin, oral cavity, esophagus, bronchus, etc.
• Glandular origin: stomach, endometrium, breast, prostate, large bowel, etc.
– The time that such lesions remain in situ before becoming invasive is unknown (some take several years)

Back 30

Anatomic site

Front 31

What kind of cells are disordered cells that proliferate rapidly and vary greatly in size and shape

Back 31

cancer cells

Front 32

What kind of cell divide in an uncoordinated manner, invading and destroying neighboring tissue?

Back 32

cancer cells

Front 33

What kind of cells are characterized by the following:
1. Local increase in cell number
• Increase in cell division (mitotic activity)
• Increase in total DNA
• Abnormal chromosomes
2. Variation of cell shape and size
3. Loss of normal arrangement of cells

Back 33

cancer cells

Front 34

What kind of cell junction change is the following: – Channels connecting adjacent cells that allow small molecules to pass between them, allowing communication and cooperation between cells
– Many carcinogens block gap junctions causing a decrease in intercellular communication, which may play a role in cancer development

Back 34

Gap junction changes

Front 35

What kind of cell junction change is the following: – An enzyme that degrades proteins
– It is not activated in normal cells
– It is activated in cancer cells, causing the degradation of the extracellular matrix during tumor cell invasion

Back 35

Plasmin junction changes

Front 36

What kind of cell junction change is the following: – The extracellular matrix is a meshwork of large organic molecules that bind cells together to make a tissue
– Normal cells are anchored to neighboring cells and to the extracellular matrix by anchoring junctions
– Normal cells do not divide unless they are anchored
– Cancer cells display anchorage-independence
-- Without being anchored they can:
• Continue to divide
• Metastasize and grow in new environments

Back 36

Anchoring junction changes

Front 37

Why do cancer cells have more metabolic demands?

Back 37

Cancer cells exhibit greater metabolic demands due to increased rates of cellular divisions.

Front 38

T/F Cancer cells engage in anaerobic glycolysis (allowing the most rapid use of glucose) even when oxygen is present.

Back 38

True

Front 39

Why is it not a good idea to diagnose cancer because of high metabolic rates?

Back 39

– Many normal tissues exhibit high glycolytic rate and
– Many neoplasms have normal glycolytic rate

Front 40

What is the cytoskeleton composed of?

Back 40

The cytoskeleton is composed of a network of protein filaments (microfilaments and microtubules)

Front 41

What does the cytoskeleton function to do?

Back 41

The cytoskeleton functions to control the cell’s shape and internal organization.

Front 42

T/F In cancer cells the filaments are not well organized resulting a rounded appearance.

Back 42

True

Front 43

What chemical is the following: – A glycoprotein
– Preset on cell surfaces in normal cells
– Serves as an anchoring molecule to:
• Hold cells in place in the tissue
• Hold receptor molecules in certain arrangement
• Help to keep the cell’s internal organization

Back 43

Fibronectin

Front 44

• In cancer cells, this chemical is defective or broken down, causing changes in:
– Cellular organization
– Cell-to-cell adhesion
– Cellular migration

Back 44

fibronectin

Front 45

T/F Normal cells show a density-dependent growth inhibition; they usually form a monolayer in a culture dish.

Back 45

True

Front 46

How do cancer cells grow?

Back 46

Cancer cells, continue to grow and pile up on top of another forming a multilayer.

Front 47

What do growth factors in normal cells do?

Back 47

Growth factors in normal cells
– Help regulate cell population density
– Include inducers and inhibitors (suppressors)

Front 48

What is the result when growth factors are unbalanced?

Back 48

Cancer may result when growth factors are unbalanced.

Front 49

What are chronically stimulated by growth inducers?

Back 49

Cancer Cells are chronically stimulated by growth inducers.

Front 50

What kind of cells do not respond to growth supressors?

Back 50

Cancer cells.

Front 51

T/F Normal cells depend on other cells for growth inducers.

Back 51

True

Front 52

T/F Cancer cells either need no growth inducers to divide, or produce their own (autocrine) growth factors.

Back 52

True

Front 53

What happens to the nucleus in cancer cells?

Back 53

The nuclei of cancer cells are often enlarged and variable in shape (instead of being round as in normal cells).

Front 54

What chromosome abnormalities commonly occur in cancer cells?

Back 54

Chromosome abnormalities such as deletions, breaks, inversions & translocations are frequent in cancer cells.

Front 55

What are substances that are either produced by cancer cells or as the body’s response to cancer cells?

Back 55

Tumor cell markers

Front 56

What are a few examples of tumor cells markers?

Back 56

They include hormones, enzymes, genes, antigens, antibodies.

Front 57

What may increased hormone levels indicate?

Back 57

• Increased hormone levels, such as insulin, in the blood may indicate:
1. Adenoma (adeno-carcinoma) of a certain endocrine gland (islet cells tumor)
2. Ectopic hormonal production: a certain type of lung cancer cells produce insulin

Front 58

Where can tumor cell markers be found?

Back 58

Tumor cell markers can be found:
– On plasma membranes of tumor cells
– In various body fluids such as blood, cerebrospinal fluid (CSF), & urine

Front 59

What are tumor cell markers used for?

Back 59

Tumor cell markers are used to:
– Screen and identify individuals at high risk for cancer
– Help diagnose the specific type of tumor
– Follow the clinical course of cancer

Front 60

Cancer risk depends on the interaction of what two factors?

Back 60

Cancer risk depends on interaction between inherited and environmental factors.

Front 61

Why is cancer genetic at the cellular level?

Back 61

At the level of the cell, cancer is genetic because the primary basis of cancer is mutations, and mutations are genetic events.

Front 62

Cancer commonly occurs in the (somatic/reproductive) cells.

Back 62

most of the genetic changes that cause cancer occur in somatic cells, not in the reproductive cells. Thus, these genetic changes (events) are not transmitted to future generations. They are genetic events, but they are not inherited!

Front 63

What kind of cells must cancer occur in to be passed on?

Back 63

Only when the genetic changes occur in reproductive cells, they pass from generation to generation.

Front 64

Environmental agents that cause cancer are called what?

Back 64

carcinogens

Front 65

How do carcinogens cause cancer?

Back 65

Carcinogens cause cancer by increasing the frequency of mutations in somatic cells.

Front 66

What is evidence that carcinogens cause cancer?

Back 66

– Epidemiological and laboratory studies:
• Cigarette smoke causes lung cancer
• Certain chemicals cause certain types of cancer
– Comparison of populations with different life-styles:
• Breast cancer is prevalent in American and Northern European women, but is more rare in developing countries
• In Japan, colon cancer is rare; Japanese who immigrated to the US have increased colon cancer incidence

Front 67

What are viruses called that cause cancer?

Back 67

oncogenic viruses

Front 68

What are the two ways in which viruses cause cancer?

Back 68

Directly and Indirectly.

Front 69

What kind of way does the following cause cancer:
– Viruses cause tissue damage, which results in healing
– Healing results in actively dividing cells
– Actively dividing cells are at higher risk of mutation

Back 69

Indirectly

Front 70

What kind of way does the following cause cancer: – Viruses invade the host’s cell
– They insert their genetic material into the cell’s DNA
– Thus causing the cell to transform into a cancer cell

Back 70

Directly

Front 71

There are 2 types of viruses that can cause cancer directly. What are they?

Back 71

Oncogenic retroviruses and Oncogenic DNA viruses

Front 72

What kind of virus is HTLV: human T cell leukemia-lymphoma virus?

Back 72

Oncogenic retroviruses

Front 73

What kind of virus is hepatitis B virus and Epstein-Barr virus?

Back 73

Oncogenic DNA Viruses

Front 74

These kind of viruses include papova-viruses, adeno-viruses, and herpes-viruses.

Back 74

Oncogenic DNA Viruses

Front 75

Hepatitis B virus, Epstein-Barr virus, and human papilloma-virus are responsible for what percent of all human cancers worldwide

Back 75

15%

Front 76

Hepatitis B virus is considered high risk factor for what kind of cancer?

Back 76

hepatocellular carcinoma

Front 77

Epstein-Barr virus can cause certain what kind of cancer in immunosuppressed individuals?

Back 77

lymphomas and nasopharyngeal cancer

Front 78

Human papilloma-virus has how many different sub-strains that cause either benign or malignant tumors

Back 78

60

Front 79

Cancer of the cervix and liver account for about what percent of virus-linked cancers.

Back 79

80%

Front 80

What usually appears to be derived from a single “outlaw” stem cell (monoclonalorigin)?

Back 80

Tumors

Front 81

Evidence indicates that tumor development requires what?

Back 81

• Evidence indicates that tumor development requires several independent rare accidents to occur together in one cell.

Front 82

Carcinogenesis is the multi-step process of tumor development, it includes what?

Back 82

– The loss of the cell’s ability to terminally differentiate
– The loss of the cell’s ability to control growth
– The cell has to travel to distant tissue and invade and colonize it

Front 83

T/F Very often there is a shirt delay between the initial causal event and the onset of cancer.

Back 83

False - Very often there is a long delay between the initial causal event and the onset of cancer.

Front 84

During what period, the cancer cells undergo multiple and successive changes?

Back 84

During the latent (delay) period, the cancer cells undergo multiple and successive changes.

Front 85

T/F Because they proliferate and divide faster, cancer cells will eventually outnumber normal cells.

Back 85

True

Front 86

What happens to the chances of getting cancer as age increases?

Back 86

In most types of cancer, the chance of getting the disease increases at a rapid rate with age.

Front 87

In theory, cancer development consists of what stages?

Back 87

Initiation, Promotion, and Progression

Front 88

What stage of cancer development consists of : - the developmental stage of cancer
– An irreversible mutation in the DNA of the cancer precursor cell after exposure to a carcinogen

Back 88

Initiation Stage

Front 89

What stage of cancer development consists of : cell proliferation and tumor development
– Promoters affect cell division by altering cellular communication and interfering with
differentiation (example: oils increase the presence of free radicals).

Back 89

Promotion Stage

Front 90

What stage of development of cancer is the following: a late stage of promotion, biological worsening
• In reality, only some cancers show this type of development

Back 90

Progression Stage

Front 91

What factors can affect the frequency of cancer?

Back 91

However, the frequency and consequences of the genetic mutations can be altered by
environmental factors.

Front 92

How is the study of carcinogens done?

Back 92

The study of carcinogens (environmental agents that cause cancer) is done either:
1. In the lab (animals):
• In experimental animals, many agents cause cancer
2. Epidemiologically (study of populations):
• The relationship between life-style and cancer is not absolutely clear