chapter 19

Question 1

Cells arise that no longer respond to normal growth control
mechanism and give rise to clones of cells to produce ________________________.

Answer 1

tumors

Question 2

benign tumors:

Answer 2

Not capable of indefinite growth and does not invade the healthy
surrounding tissue extensively

Question 3

malignant/cancerous tumor:

Answer 3

Continues to grow and becomes progressively invasive

Question 4

Small clusters of cancerous vessels dislodge from a tumor, invade the
blood or lymphatic vessels, and carried to other tissues, where they continue to proliferate

Answer 4

metastasis

Question 5

Cancers are classified according to their ___________________origin

Answer 5

embryonic tissue

Question 6

tumors that develop from epithelial origins

Answer 6

carcinomas
-skin, gut, epithelial linings

Question 7

derive from mesodermal connective tissue

Answer 7

sarcomas
-bone, fat, cartilage tissue

Question 8

derive from hematopoietic stem cells

Answer 8

lymphomas, myelomas, and leukemias

Question 9

change that a normal cell undergoes as it becomes malignant

Answer 9

transformation

Question 10

What factors can induce transformation?

Answer 10

-radiation
-carcinogens (chemicals)
-viruses
-expression of oncogenes

Question 11

a gene that encodes a protein capable of inducing cellular transformation

Answer 11

oncogene

Question 12

how are oncogenes derived from viruses written compared to those derived in normal cells?

Answer 12

v-onc
c-onc

Question 13

proto-oncogenes:

Answer 13

enhance cell survival when their control mechanisms fail

Question 14

tumor-suppressor genes:

Answer 14

allow cancer cell survival when they fail

Question 15

________________gene problems can also lead to abnormal cell survival

Answer 15

apoptosis

Question 16

what is involved in induction of cellular proliferation?

Answer 16

-growth factors and receptors
-products involved in signal transduction

Question 17

what is involved in inhibition of cellular proliferation?

Answer 17

tumor suppressor genes

Question 18

What is Bcl-2 involved in?

Answer 18

regulation of apoptosis

Question 19

what is Burkitt’s lymphoma an example of?

Answer 19

DNA alterations/chromosomal translocations that induce malignant transformation

Question 20

Describe tumor-specific antigens (TSA):

Answer 20

-unique to tumor cells, don’t occur in normal cells
-may result from mutations that generate altered cellular proteins
-cytosolic processing of these proteins leads to novel peptides that are presented with Class I MHC
**uncommon

Question 21

Describe tumor-associated antigens (TAA):

Answer 21

-not unique to tumor cell
-may be antigens normally expressed on fetal cells, when immune systems cannot react to them
-not normally expressed on adult cells
**common

Question 22

Describe chemically or physically induced tumor antigens:

Answer 22

-Two carcinogens: Methylcholanthrene and UV light
-Tumor antigens can be distinct and the immune response to one tumor doesn’t protect against the other tumor

Question 23

Describe viral induced tumor antigens:

Answer 23

Viruses induced tumors express tumor antigens shared by all tumors induced by the same virus.

Question 24

Oncofetal tumor antigens:

Answer 24

Antigens appear early in embryonic development, before the immune system mature; if the antigens appears later on cancer cells, they are recognized as non-self and induce an immunologic responses

Question 25

Oncogen proteins as tumor antigens:

Answer 25

Breast cancer cells up-regulate oncogen-encode Neu protein, a growth factor receptor

Question 26

How are adaptive cell types involved in eradication?

Answer 26

-lack of T cells leads to increases in cancer -Tumor-inflitrating lymphocytes (TILS) (T, NKT, NK) -B cells generate anti-tumor antibodies against tumor-specific antigen * Promotes tumor-cell recognition and lysis –*May block CTL access to tumor Ag, though

Question 27

what are some immune responses to cancers?

Answer 27

-CD8 T cells recognize and kill cells that express foreign peptides -antibodies target tumor antigens leading to complement activation and ADCC

Question 28

NK cells in response to cancer:

Answer 28

– Respond in the absence of MHC class I – Can bind antibody-coated tumors leading to ADCC

Question 29

macrophages in response to cancer:

Answer 29

– Cluster around tumors leading to regression – Not MHC restricted – mediated ADCC – Antitumor lytic enzymes and TNF-α

Question 30

The role of cytokines in controlling cancer:

Answer 30

* IFN-γ * All interferon types enhance tumor-cell removal activities of immune cells * IL-12 – Encourages DCs to activate strong TH1 and CTL responses * TNF-α may promote or inhibit anti-cancer effects; role in cancer immunity is complex

Question 31

How can enhancing anti-tumor antibodies promote cancer?

Answer 31

– May bind and block tumor Ag that would otherwise be targeted by CTLs – May form complexes with free tumor Ag

Question 32

active immunosuppresion in tumor microenvironments can promote cancer because?

Answer 32

* Soluble factors released can suppress immunity – TGF-β – IL-10 – Induction of TREG cells

Question 33

How do tumors evade the immune system?

Answer 33

1. Reduced MHC expression in tumor cells 2. Tumor cell subversion of apoptosis signals: -Upregulation of anti-apoptotic mediators -Expression of mutated or absent death receptors 3. Tumor cells may provide poor costimulatory signals ---leading to clonal anergy

Question 34

What are the 4 categories of cancer immunotherapy?

Answer 34

– Chemotherapies aimed at blocking DNA synthesis and cell division – Hormonal therapies which interfere with tumor-cell growth – Targeted therapies such as small molecule inhibitors of cancer – Immunotherapies which induce or enhance the anti-tumor immune response

Question 35

what will be the benefit of harvesting and transfecting tumor cells with a gene for GM-CSF?

Answer 35

This cytokine will promote DC presentation of tumor Ag, stimulating CTL responses

Question 36

what is it called when cancer cells develop their own blood supply?

Answer 36

angiogenesis