Lecture 5

Question 0

Helicobacter pylori causes

Answer 0

Chronic inflammation via stomach ulcers, increasing risk of cancer.

Question 1

What % of cancers are environmental vs hereditary?

Answer 1

90-95% enviro, 5-10% hereditary

Question 2

Rous sarcoma

Answer 2

Naturally occurring retrovirus, first oncovirus described

Question 3

DNA viruses that contribute to cancer

Answer 3

HPV (cervical, penile, anal), Epstein-Barr (herpes) (Burkitt’s lymphoma), Hep B (liver carcinoma).

Question 4

RNA viruses that contribute to cancer

Answer 4

Human T-cell leukemia, Hep C (liver carcinoma), retroviruses and endogenous viruses.

Question 5

3 main retrovirus genes

Answer 5

Pol, env, gag

Question 6

Retroviruses cause tumors in two ways

Answer 6

1. Acute transforming viruses 2. Non acute (chronic) transforming viruses

Question 7

Acute transforming viruses

Answer 7

Carry oncogenes in their RNA genome, CAN transform cells in culture

Question 8

Non-acute (chronic) transforming viruses

Answer 8

Don’t carry oncogenes, CANNOT transform cells, tumorigenesis occurs over time

Question 9

Viral oncogene

Answer 9

Gene from the virus itself

Question 10

Non-viral oncogene

Answer 10

Proto-oncogene or oncogene stolen from host cell, typical in its inactive form. Can incorporate with retroviral genome and yield a highly oncogenic retrovirus.

Question 11

Oncolytic viruses

Answer 11

Attenuated virus that targets, infects, and kills cancer cells specifically.

Question 12

Mutations in the sperm or egg

Answer 12

Germline mutations

Question 13

Mutations in adult differentiated cells

Answer 13

Somatic mutations

Question 14

The degree to which a possessed trait is expressed

Answer 14

Penetrance

Question 15

The number of carriers of a specific allele in a population at a given time

Answer 15

Prevalence

Question 16

How is the function of mutated proto-oncogenes impacted?

Answer 16

Mutations in proto-oncogenes are gain of function mutations

Question 17

How many mutated alleles are necessary for oncogenic expression?

Answer 17

One mutated allele –> dominantly acting

Question 18

Four mechanisms of oncogene activation

Answer 18

Retroviral integration, deletion/point mutation, gene amplification, chromosomal rearrangement (translocation).

Question 19

Retroviruses can bring a strong ____ close to the proto-oncogene to activate it

Answer 19

Promoter

Question 20

Mutations can alter ____

Answer 20

Protein activity

Question 21

Gene amplification can lead to

Answer 21

Overexpression

Question 22

Fusion proteins with cancerous activity can be generated by

Answer 22

Chromosomal rearrangements

Question 23

Chromosomal rearrangements can activate proto-oncogenes by

Answer 23

Bringing a string enhancer close to the gene

Question 24

The three most common coded-for domains of oncogenes are

Answer 24

Protein kinases, DNA binding, transcriptional regulation

Question 25

Philadelphia chromosome

Answer 25

9;22 translocation, fuses bcrl and c-abl

Question 26

Oncogene that helps transmit extra cellular growth signals to the nucleus

Answer 26

Ras

Question 27

Mutated Ras is locked into its activated conformation by

Answer 27

A mutation that prevents it from hydrolyzing it’s attached GTP

Question 28

Nuclear oncogene that acts as a transcription factor

Answer 28

MYC

Question 29

What does MYC regulate?

Answer 29

Genes affecting apoptosis, proliferation, and immortalization

Question 30

What events can activate MYC?

Answer 30

Retroviral insertion, chromosomal rearrangement, gene amplification