Tumor Growth & Progression

Question 1

What is a psr?

Answer 1

Probability of self renewal in a cell population scaled from 0.00 (0%) - 1.00 (100%)

Question 2

What does a psr of 0.50 indicate?

Answer 2

Stable cell population

Question 3

What does a psr of 0.52 indicate?

Answer 3

malignancy

Question 4

What does a psr of 0.49 indicate?

Answer 4

Slow decline & decay of a tissue cell # that will eventually shrink and disappear

Question 5

What is the goal of cancer treatment in regards to psr?

Answer 5

To get the psr of the neoplastic cells below 0.50

Question 6

What is a tumor growth fraction?

Answer 6

Ratio of cell proliferation to cell loss

Question 7

What are the factors that influence tumor growth?

Answer 7

tumor angiogenesis:
- Oxygen and nutrient supply
- Metastasis
- Tumor size
- growth factors (VEGF and FGF) & inhibitors (p53?)

Question 8

What is the purpose of angiostatin?

Answer 8

To stop blood vessel growth and supply to tumors

Question 9

What is vascular endothelial growth factor?

Answer 9

Growth factor that gives a tumor the ability to undergo angiogenesis and gain capillaries and a blood supply

Question 10

What is fibroblast growth factor?

Answer 10

Growth factor that gives a tumor a connective tissue stroma for support

Question 11

What are the general steps (cellular basis) of metastasis of carcinomas?

Answer 11

• Detachment via loss of cadherin molecules
• Attachment to basement membrane/ECM with laminin and fibronectin
• Secretion of proteolytic enzymes (protease) to degrade ECM
• Movement of tumor cells through BM into vessels via cytokines (autocrine motility factor)

Question 12

What is tumor progression?

Answer 12

The orderly progression from a preneoplastic lesion to a benign tumor and ultimately an invasive cancer

Question 13

What cancer is the exception to normal tumor progression?

Answer 13

Colon carcinoma

Question 14

What is important about genetic instability in regards to neoplasms?

Answer 14

Increased rate of random, spontaneous mutations during clonal expansion will increase chances of developing a neoplasm

Question 15

What molecule is lost when a tumor cell detaches and attempts to metastasize?

Answer 15

Cadherin

Question 16

What molecules are expressed when a tumor cell that has detached from the primary tumor tries to attach to the basement membrane of a distant tissue?

Answer 16

Laminin and fibronectin

Question 17

What enzyme is primarily expressed by a metastatic tumor cell that has spread to a distant tissue that degrades the ECM of that tissue?

Answer 17

Matrix metalloproteases

Question 18

What cytokine allows for movement of tumor cells through the basement membrane and into vessels?

Answer 18

Autocrine motility factor
(carrot for the horse)

Question 19

What are the most common sites for metastasis of malignant neoplasms?

Answer 19

Liver
Lung
Bone
Brain

Question 20

What is the most common site for metastasis in the body?

Answer 20

Lung

Question 21

What is organ tropism?

Answer 21

Neoplastic cells preference to have a selective site for metastasis that cannot be explained by natural pathways of drainage

Question 22

What is the metastatic pattern of lung carcinoma?

Answer 22

Adrenal Glands (#1) and brain

Question 23

prostate carcinomas metastasize to ____

Answer 23

bone

Question 24

Most tumors elicit a ____ inflammatory response?

Answer 24

Chronic

Question 25

What are genetically identical mice in animal lab studies called?

Answer 25

Syngeneic mice

Question 26

What are the four sub-experiments conducted on mice that led to the theory that the body has natural defenses against cancer cells?

Answer 26

- Mice injected with cancer/oncogene to prove oncogenic effect (malignant tumor develops) - tumor excised from mouse--> tumor cells injected into syngeneic mice -> tumor develops - in untreated mice, tumor metastasizes & kills mice - when reinjected into original treated mice, mouse rejects tumor & survives (developed immunity)

Question 27

What do mouse experiments with tumor injections demonstrate in regards to our immune system?

Answer 27

Our body has immune responses and defenses to oncogens (immunosurveillance; does NOT tell us why/how)

Question 28

What is the upper limit of tumor burden for malignancy?

Answer 28

1 Kg or 10^12 (One trillion) tumor cells

Question 29

What is the lower limit of clinical detection for tumors?

Answer 29

1 cm^3 or 10^9 (One billion) tumor cells

Question 30

At diagnosis, approximately ____ of all cancer patients are already metastatic

Answer 30

1/2

Question 31

What is tumor immunosurveillance?

Answer 31

Recognition and destruction of tumor cells by the immune system

Question 32

What is a tumor specific antigen?

Answer 32

Cell surface molecule produced ONLY by tumor cells

Question 33

What is a tumor associated antigen (TAA)?

Answer 33

Normal molecule made by normal tissues that are increased with tumors

Question 34

What is an example of a tumor associated antigen (TAA)?

Answer 34

**Prostate specific antigen** (PSA) expressed in prostate adenocarcinoma

Question 35

What are natural killer cells?

Answer 35

Lymphocyte-activated killer cells that can lyse tumor cells without recognizing TSA

Question 36

What cytokine activates natural killer cells?

Answer 36

IL-1

Question 37

What are cytotoxic CD8+ T lymphocytes?

Answer 37

lymphocytes that recognize TSAs and lyse tumor cells

Question 38

Cytotoxic T lymphocytes require the presence of __________ to lyse a tumor cell

Answer 38

Tumor specific antigen (TSA)

Question 39

What do patients with leukemia often die of?

Answer 39

Anemia or systemic infection due to a weakened immune system

Question 40

When does a tumor cell require its own blood supply?

Answer 40

10^6 or 1 million cells

Question 41

What white blood cells aid in tumor immunity?

Answer 41

CD8+ cytotoxic T lymphocytes and NK cells