Lec. 4 Oncogenic Viruses

Question 1

Name the features of cancer cells that differentiate them from normal cells…

Answer 1

Tumorigenicity
Lack of differentiation
Immortality
Lack of contact inhibition
Resistance to apoptosis
Chromsome abnormalities

Question 2

Name some photo-oncogenes that control cell growth…

Answer 2

myc: Transcription factor
src: Membrane signaling of growth factor binding
ras: signaling transduction from surface receptors
sis: Platelet-derived growth factor

erb B: Growth factor receptor

fms: Growth factor receptor

LMO2: Hematopoiesis

Question 3

What are the two major regulators of the cell cycle?

Answer 3

p53 and Rb

Question 4

Acute myeloblastic leukemia has over expression what proto-oncogene?

Answer 4

mos

Question 5

Chronic myelogenous leukemia has over expression what proto-oncogene?

Answer 5

abl

Question 6

Acute promyelocytic leukemia has over expression what proto-oncogene?

Answer 6

fes

Question 7

Acute lymphocytic leukemia has over expression what proto-oncogene?

Answer 7

LMO2

Question 8

Ovarian cancer has over expression what proto-oncogene?

Answer 8

myb

Question 9

Breast cancer has over expression what proto-oncogene?

Answer 9

her-2/neu

Question 10

What do RNA oncogenic viruses do to cause mutations causing cancer?

Answer 10

carry activated oncogenes, or insert their promoter and activate an oncogene

Question 11

What do DNA oncogenic viruses do to cause mutations causing cancer?

Answer 11

Degrade cell cycle genes– disturb the cell cycle and prevent apoptosis

p53 and Rb can be inactivated by viral proteins

Question 12

What does SV40 virus have to do to cause tumor growth?

Answer 12

Inactive p53 and Rb using the expression of T antigen, which must be activated at all times to cause tumor growth

NO human tumors express SV40 virus

Question 13

Adenoviruses causes what in rodents and what in humans and how?

Answer 13

A group of human viruses–can cause cancer in rodents- has E1A and E1B which are analogous to T antigen found in SV40 virus and are turned on all the time in transformed cells

Does NOT cause cancer in humans—only colds and sore throats

Question 14

Patients with SCID IL2 deficiency have been treated with gene therapy and cure of their disease, however there was some major adverse side effects from the gene therapy. What was the major adverse side effect and how was it caused?

Answer 14

4/9 developed T cell leukemia due to insertion of virus adjacent to LMO2 oncogene- 1 died.

Question 15

Name some naturally occurring animal centers that are infectious and caused by viruses…

Answer 15

Breast cancer of mice–caused by mammary tumor virus
Leukemia of domestic cats–caused by Feline leukemia virus
Lymphomas of chickens– caused by Marek’s disease virus

Question 16

What are the low risk human papillomaviruses and what do they cause?

Answer 16

HPV 2 and 4 causing warts

Question 17

What are the intermediate risk human papillomaviruses and what do they cause?

Answer 17

HPV 11- laryngeal papillomas

Question 18

What are the high risk human papillomaviruses and what do they cause?

Answer 18

HPV 16 and 18- squamous cell carcinomas of the cervix, penis, and oropharynx

Question 19

What are the two genes of the human papillomaviruses that function similar to the T antigen in the SV40 virus?

Answer 19

E6 and E7

Question 20

What does the HPV vaccines available reduce the incidence of?

Answer 20

cervical intraepithelial neoplasia (CIN)

Question 21

What gene is a suppressor of the E6 and E7 genes?

Answer 21

E2

Question 22

What does the E6 gene bind and what does this lead to?

Answer 22

p53 leading to degradation by ubiquitin pathway

Question 23

What does the E7 gene bind and what does this lead to?

Answer 23

Rb leading to the prevention of Rbs interaction with E2F

Question 24

Loss of the function of what gene will lead to the over expression of E6 and E7?

Answer 24

E2

Question 25

Name the virus…A herpes virus that causes mononucleosis in the western world, but is associated with childhood lymphoma (Burkitt’s) in parts of Africa and in patients with AIDS…

Answer 25

Epstein-Barr Virus

Question 26

Tumors caused by the Epstein-Barr virus have a translocated oncogene which is over-expressed. What is this oncogene?

Answer 26

Myc

Question 27

The Epstein-Barr virus is associated with what type of cancer in Asia?

Answer 27

Naso-pharyngeal

Question 28

What co-factors are involved in the development of Burkitt’s lymphoma and Naso-pharyngeal cancers caused by the Epstein-Barr virus?

Answer 28

Malaria infections in Africa–Burkitt’s Lymphoma

Food preservatives in Asia- Naso-Pharyngeal cancer

Question 29

What translocation occurs that causes Burkitt’s lymphoma?

Answer 29

Translocation from 8-14 of the myc gene

Question 30

What are the characteristics of B-cell lymphomas seen in the western world?

Answer 30

Most are EBV (-)

Seen in patients with AIDS or immunosupressed patients

Question 31

What viruses cause chronic hepatitis predisposing the patient to cirrhosis and liver cancer?

Answer 31

Hepatitis viruses B and C

Question 32

Human T-cell lymphotropic viruses are _____ viruses with no oncogene.

Answer 32

RNA

Question 33

What is over expressed in Human T-cell lymphotropic virus (HTLV-1 and 2) and what causes it?

Answer 33

Interleukin-2 and the receptor for IL-2 is over-expressed caused by the TAX gene

Question 34

What does Human T-cell lymphotropic virus cause and where is it most prevalent?

Answer 34

Leukemia and lymphoma

Prevalent in Caribbean countries

Question 35

What is Kaposi sarcoma herpes virus associated with?

Answer 35

Kaposi’s sarcoma in patients with HIV