Signal Transduction and Oncogenesis

Question 1

What is Cancer?

Answer 1

A group of heterogeneous pathologic states in which cells multiply abnormally and invade surrounding tissues

Question 2

How many types of human cancers are there?

Answer 2

More than 200

Question 3

What are the SIX features of cancer cells?

Answer 3

1. Grow out of control
2. Interfere with normal tissue
3. Suffer loss of regulatory system function
4. Display clonality
5. Display anchorage independence
6. De-differentiation

Question 4

What are the FOUR major groups of human cancers?

Answer 4

1. Carcinoma
2. Sarcoma
3. Leukaemias
4. Lymphomas

Question 5

What is Carcinoma?

Answer 5

Cancer of epithelial cells

Question 6

What is Sarcoma?

Answer 6

Cancer of connective tissue

Question 7

What are Leukaemias?

Answer 7

• A class of sarcoma
• Grow as individual cells in the blood or bone marrow

Question 8

What are Lymphomas?

Answer 8

• A class of malignant sarcoma
• Solid tumours of lymphocytes and plasma cells

Question 9

How are cancers classified?

Answer 9

1. Site of origin
2. Cell type
3. Named after discoverer

Question 10

What are the FOUR general steps in tumour staging?

Answer 10

1. Formation
2. Invasion of surrounding tissues
3. Entry of cancer cells into circulation
4. Metastasis

Question 11

What are the TWO types of tumour?

Answer 11

1. Benign
2. Malignant

Question 12

Which tumour type is able to metastasize?

Answer 12

Malignant

Question 13

What are Invadopodia?

Answer 13

Finger-like plasma membrane protusions formed by cancer cells during migration

Question 14

What are Oncogenes?

Answer 14

Genes that encode oncoproteins that promote cancer

Question 15

What is a Proto-Oncogene?

Answer 15

Normal version of a gene involved in control of cell growth / division

Question 16

How do Proto-Oncogenes become Oncogenes?

Answer 16

Through mutation (point, insertion, or deletion)

Question 17

What is an example of a sis oncoprotein?

Answer 17

Platelet Derived Growth Factor (PDGF)

Question 18

What is sis oncogene?

Answer 18

First oncogene to be identified as having homology to a known cellular gene

Question 19

What cancers are a result of oncogenic Growth Factors?

Answer 19

Meningiomas and some skin neoplasms

Question 20

When do RTKs become oncogenic?

Answer 20

If active even in the absence of a ligand

Question 21

What is VEGF?

Answer 21

Growth factor important in angiogenesis (formation of blood vessels by tumour)

Question 22

What cancers are a result of oncogenic RTKs?

Answer 22

Breast & Colon

Question 23

What is the function of p53?

Answer 23

• Senses DNA damage (DNA damage)
• Halts cells from proliferating
• Causes cells to undergo apoptosis

Question 24

Which protein is p53 normally sequestered to?

Answer 24

MDM2

Question 25

How does p53 sense DNA damage?

Answer 25

Through another protein called ATM that signals p53 by phosphorylation

Question 26

What can cause inactivation or mutations in p53?

Answer 26

Chemical carcinogens
* cigarette smoke inactivates p53
* asbestos causes mutations in p53

Question 27

How does a tumour inactivate p53?

Answer 27

Increasing MDM2 levels

Question 28

Where do p53 mutations generally occur?

Answer 28

DNA binding domain