White 6 "Cancer 1"

Question 1

define cancer

Answer 1

a disease in which an individual mutant clone of cells begin by prospering at the expense of its neighbor cells

Question 2

What are the properties of cancer cells?

Answer 2

• cells are growing out of control
• become self sustaining, do not need signals to grow
• release autocrine growth factor
• cancer cells ignore apoptosis signals
• self-sufficient
• defective in cell cycle control mechanisms to stop the cell cycle
• gets help from stroll cells
• indices angiogenesis
• no replicative senescence

Question 3

What are the basic differences between cancer cells and normal cells?

Answer 3

Cancer cells require little growth factors
normal cells have a strong requirement for growth factors

cancer cells become independent of stimulation that is normally required by cells the proliferate (decontrolled proliferation)

Question 4

What are the two heritable properties of cancer cells

Answer 4

1. reproduce in defiance of normal restraints on cell division and cell growth
2. invade areas that are normally reserved for other cells

Question 5

Describe how a tumor kills

Answer 5

it squeezes and destroys blood vessels and nerves until an organ stops functioning normally

Question 6

Describe benign tumors

Answer 6

the neoplastic cells do not become invasive; is not cancer

Question 7

Describe the 3 classifications of cancer

1. carcinomas
2. sarcomas
3. leukemias and lymphomas

Answer 7

1. carcinomas are from epithelial cells
2. sarcomas are from connective and muscle tissues
3. leukemias and lymphomas are from white blood cells and their precursors

Question 8

Describe metastases

Answer 8

characteristic of cancer
invasive property
cancer cells break loose and enter into the blood or lymph and travel to new areas and form secondary tumors

THIS KILLS

Question 9

Describe the development of cancer

Answer 9

• multiple mutational events
• all tumors are from a single ancestor
• mutations lead to a proliferative advantage and allow cells to grow rapidly
• develop slowly

Question 10

Describe the development of colon cancer

Answer 10

• mutation in the APC gene in certain cells which have an advantage in cell growth
• polyps form which are technically benign tumors
• mutation in the Ras gene
• loss of tumor suppressor
• tumor moves into the blood stream
• gains capacity to invade
• NOW malignant

Question 11

What is evidence that cancers are derived from a single cell?

Answer 11

• philadelphia chromosome (translocation between chi 9 and 22)
• smaller chromosome
• responsible for myelogenous leukemia
• comes from a single cell

Question 12

What are the two types of carcinogens?

Answer 12

chemical and radiation

Question 13

What are the two things that cancerous growth depends on?

Answer 13

defective apoptosis or defective growth

Question 14

Describe the steps in the process of metastasis

Answer 14

1. cells grow as a benign tumor in the epithelium
2. cells become invasive and enter the capillary
3. cells adhere to the blood vessel in the liver
4. cells escape from the blood vessel to form micrometastasis
5. colonize liver forming full blown mets

Question 15

Describe angiogenesis

Answer 15

formation of new blood vessels

• tumors must get oxygen and nutrients like normal cells
• release factor to induce new blood vessel formation
• come from pre-existing blood vessel

Question 16

Define neovascularization

Answer 16

formation of new blood vessels from scratch

Question 17

What is the biggest environmental cause of cancer

Answer 17

tobacco

90% of people with lung cancer smoked

Question 18

What are the two genetic causes of cancer

Answer 18

1. tumor suppressor genes

2. oncogenes

Question 19

What are the two types of broad mutations that regulate cell proliferation?

Answer 19

1. overactivity mutations: gain of function of the oncogenes- single mutation event and activation of a gene causing proliferation
2. under activity mutations: loss of function in the tumor suppressor genes that inhibit growth

Question 20

Describe the differences between oncogenes and tumor suppressor genes

Answer 20

oncogenes are the gas pedal (gain of function) and the tumor suppressor genes (loss of function) are the brakes

oncogenes- one mutation leads to a dominant effect

tumor supressors- both copies must be mutated as it is recessive

Question 21

Describe DNA maintenance genes

Answer 21

• subset of tumor suppressor genes
• mutations involve inactivation of the caretaker genes that create stability
• include DNA repair genes

Question 22

Describe retroviruses and their relation to cancer and oncogenes

Answer 22

contain an RNA genome that can be transformed into DNA and integrated into the host

• transformed cells are small colonies of proliferative cells that are caused by oncogenes
• hijack proto-oncogenes and activate them via over-expression or cause mutations

Question 23

Describe Ras

Answer 23

• first human oncogene

- monomeric GTPase for signal transduction

Question 24

What are Ras oncogenes?

Answer 24

cannot shut off by hydrolyzing GTP to GDP

Question 25

What are the 4 mutations that lead to the activation of proto-oncogenes into oncogenes

Answer 25

only one allele needs to be present for the activity to occur

1. deletion or point mutation in the coding sequence
2. regulatory mutation
3. gene amplification
4. chromosome rearrangment

Question 26

Describe deletion or a point mutation in the activation of an oncogene

Answer 26

deletion or mutation in the coding sequence which makes a hyperactive protein

Question 27

Describe the regulatory mutation in the activation of an oncogene

Answer 27

produce more than a normal protein which leads to a promoter mutation

Question 28

Describe gene amplification in the activation of an oncogene

Answer 28

several copies of a normal protein are produced instead of one copy

Question 29

Describe chromosomal rearrangement in the activation of an oncogene

Answer 29

beings new regulatory sequence that causes the overproduction or creates overactive fusion protein

Question 30

Describe ligands and their relationship to cancerous cells

Answer 30

if produced consitutively, can cause proliferation and growth all the time; cancer cells can produce their own autocrine signaling

Question 31

Describe the receptors and their relationship to cancerous cells

Answer 31

tyrosine kinase receptors- when RTKs constitutively produced do not need a ligand

Question 32

Describe the transcription factor and their relationship to the cancerous cells

Answer 32

These proteins constantly induce transcription

• fos and jun activate gene expression including those important for cell cycle progression
• overproduction can lead to these to act as oncogenes

Question 33

Define cell cycle proteins

Answer 33

anything that can cause cell proliferation; overproduction leads to cancer

Question 34

What does Bcl2 do?

Answer 34

promotes cell survival despite DNA damage
-rearrangement mutation
via translocation this places Bcl2 under a new enhancer that induces a greater expression
-ACTIVE in B cells