Cancer Biology

Question 1

Malignant v. Benign

Answer 1

Malignant: Cancerous tumors, exhibit uncontrolled growth; abnormal cell shape and size; invade and metastasize; life threatening (esp. later stages)
Benign: non-cancerous tumors; abnormal cell growth; normal cell shape/size; does not invade or metastasize; can be life threatening by interfering with surrounding tissue or excreting hormones

Question 2

How are tumors classified

Answer 2

Based on the originating site of the tumor

Question 3

Endoderm

Answer 3

forms the inner layer of cells
makes up epithelial lining go internal organs
ex: lining of liver, stomach, lungs

Question 4

mesoderm

Answer 4

forms middle layer of cells
makes up the connecting and supporting tissues
ex: bone, muscle, blood

Question 5

ectoderm

Answer 5

forms outer layer of cells
makes up skin and nervous system
ex: neurons, skin, pigment cells

Question 6

Where do carcinomas occur

Answer 6

occurs in epithelial cells covering the surface of the body and internal organs
makes up about 80-90% of all cancers

Question 7

Where do Adenocarcinomas form

Answer 7

epithelial cells that have glands
ex: pancreatic adenocarcinoma forms from pancreatic exocrine cells that secrete digestive enzymes

Question 8

Examples of squamous cell carcinomas

Answer 8

anal, cervical, endometrial

Question 9

Examples of adenocarcinomas

Answer 9

breast, lung, colon, and prostate

Question 10

Where do melanomas occur

Answer 10

melanocytes: pigmented ectodermal cells of the skin and eye

Question 11

Where do Nueroectodermal tumors arise

Answer 11

From ectodermal cells in the central and peripheral nervous system

Question 12

Examples of nueroectodermal tumors

Answer 12

gliomas, schwannomas, and nueroblastomas

Question 13

Where do sarcomas occur

Answer 13

occur in tissues of mesodermal origin

Question 14

What are sarcomas

Answer 14

solid tumors in connective and supporting tissues like blood vessels, fat, and muscle

Question 15

Examples of sarcomas

Answer 15

hemangiosarcoma (blood vessels); liposarcoma (fat); leimuosarcoma (smooth muscle)

Question 16

Most common sarcoma

Answer 16

osteosarcoma (bone)

Question 17

What is Leukemia

Answer 17

cancers of the bone marrow (liquid tumors)

Question 18

What does Leukemia cause

Answer 18

overproduction of immature white blood cells

Question 19

examples of leukemia

Answer 19

acute/chronic lymphoblastic leukemia (ALL/CLL); acute/chronic myeloid leukemia (AML/CML)

Question 20

What are lymphomas

Answer 20

cancers in the glands or nodes of the lymphatic system (solid tumor)

Question 21

Categories of lymphoma

Answer 21

Hodgkin lymphoma
Non-Hodgkin lymphoma

Question 22

Four stages do Carcinogenesis

Answer 22

1. Initiation
2. Promotion
3. Progression
4. Invasion and Metastasis

Question 23

Initiation stage of carcinogenesis

Answer 23

creation of a single malignant stem cell

Question 24

Initiating a mutation

Answer 24

Can be inherited through gremlin or somatic

Question 25

latency period of initiation stage

Answer 25

time from the initial exposure to detectable tumor

Question 26

Characteristics of initiated cells

Answer 26

appear normal
potential to seed tumor
permanently altered
do not always progress to a tumor

Question 27

Promotion stage of carcinogenesis

Answer 27

• cells acquire a selective growth advantage
• rapid growth of abnormal cells

Question 28

At what stage of carcinogenesis does a small tumor population start to form

Answer 28

promotion

Question 29

Why does growth occur in promotion stage?

Answer 29

mutations formed during mitosis
carcinogen exposure
hormonal/ dietary influences

Question 30

Progression Stage of Carcinogenesis

Answer 30

tumor gains properties that allow it to function independently of the surrounding tissue

eventual cells progress to become fully malignant

Question 31

Invasion and Metastasis stages of Carcinogenesis

Answer 31

tumor gains the ability to invade neighboring tissues, eventually entering blood or lymphatic system and metastasize to new tissues

Question 32

what is intravastation

Answer 32

cancer cells enter the blood or lymphatic system

Question 33

what is extravasation

Answer 33

cancer cells exit the vessels at distant sites

Question 34

what is the main cause of cancer mortality

Answer 34

metastasis

Question 35

Hallmarks of Cancer

Answer 35

-sustaining proliferative signaling
- evading growth suppressors
- activating invasion and metastasis
- enabling replicative immortality
- inducing angiogenesis
- resisting cell death

Question 36

How do cancer cells sustain chromic proliferation

Answer 36

by manipulation normal growth signals that control entry into and progression through cell growth and division cycle
Examples:
- produce growth factor ligands
- sending signaling to normal nearby cells which respond by producing growth factors
- elevate levels of receptor proteins localized at the cancer cell surface

Question 37

What does cancer cells escaping negative cellular regulators that limit cell growth and division cause

Answer 37

progression through cell cycle
loss of contact inhibition to neighboring cells
hijacking normal cell processes to stimulate malignancy

Question 38

how do cancer cells evade apoptosis

Answer 38

loss of DNA damage sensing p53
Increase expression of antiapoptotic regulators
increase expression of survival signals
down regulate proapoptotic factors

Question 39

angiogenesis

Answer 39

process of sprouting new blood vessels from existing ones

Question 40

How can tumors sustain growth

Answer 40

activating “angiogenic switch” during tumorigenesis

Question 41

what is the APC gene involved in

Answer 41

transcription, cell adhesion, microtubilar cytoskeleton, cell migration, apoptosis, cell proliferation

Question 42

How many copies of the APC gene is required for tumor formation

Answer 42

both copies

Question 43

Is the loss of APC alone sufficient to cause cancer

Answer 43

no- requires additional somatic mutations to lead to additional growth