Cancer: Causes and Demographics

Question 1

explain how UV radiation leads to cancer

Answer 1

DNA damage occurs in outer layer of cells
(normally apoptosis is induced)

p53 mutants can not undergo apoptosis

mutants proliferate and begin replacing cells that would normally undergo apoptosis

Question 2

normal cells do not express what type of enzyme?

Answer 2

telomerase

Question 3

normally when telomeres are shortened during replication…

Answer 3

cell division is stopped and the cell undergoes apoptosis

Question 4

abnormally when telomeres are shortened…

Answer 4

telomerase is activated and telomeres are lengthened, replication continuous indefinitely and chromosomes do not get shorter

Question 5

cancer cells expressing telomerase causes

Answer 5

indefinite replication

Question 6

describe cancer stem cells

Answer 6

undifferentiated cells that become mutated, then acquire additional mutations initiating a cancerous tumor

Question 7

if tumors contain CSCs it may have

Answer 7

unlimited proliferation

Question 8

how do CSCs cause tumor recurrence

Answer 8

b/c they’re efficient at metastasis and chemo-resistance

Question 9

who proposed normal blood stem cells accumulate rare mutation causing them to become cancerous

Answer 9

Irving Weissman (2005)

Question 10

prove to Irving Weissman’s theory

Answer 10

• blood stem cells live longer than regular blood cells allowing them to acquire mutations that can become cancerous
• blood stem cells are self-renewing surviving in the body over a lifetime

Question 11

what are 3 challenges to Irving Weissman’s theory?

Answer 11

1. identify the mutation in several acute myeloid leukemia cells
2. isolate and analyze rare, pre-cancerous stem cells
3. determine which mutations were present in the normal stem cells

Question 12

give an example of correlational data

Answer 12

as cigarette consumption increased so did the lung cancer death rate

Question 13

what concept supports a suspected carcinogen as the cause for cancer?

Answer 13

the dose-response concept

Question 14

what cancer is caused by ppl who drink and smoke?

Answer 14

oropharyngeal cancer

Question 15

why is the relative risk of developing oropharyngeal cancer much much higher in ppl who are both heaving drinkers and smokers

Answer 15

b/c alcohol is a vasodilator which will dilate lung blood vessels increasing the exposure/absorption of cigar carcinogens

Question 16

in cancer risk and environment, what environments had the highest mortality rates

Answer 16

tobacco and diet

Question 17

why do southern state w/ higher sunlight intensity have higher cancer rates

Answer 17

the increase in elevation means the atmosphere is thinner increasing the sunlight intensity

Question 18

what type of cancer was ID when sarcoma tissue was removed from a chicken

Answer 18

rous sarcoma virus

Question 19

give an example of a proven human carcinogen that also causes cancer in humans

Answer 19

mustard gas (lung cancer)

Question 20

give an example of some medications that can cause cancer and what type of cancer they cause

Answer 20

estrogens (a hormone) causing cancer in the breasts, uterus, and vagina

Question 21

secondary contributors include

Answer 21

-inflammation
-obesity

Question 22

how can inflammation be a secondary contributor?

Answer 22

bc post-inflammatory factors promote tumor growth

Question 23

how can obesity be a secondary contributing factor to cancer

Answer 23

changes in gut microbiome can create DNA-damaging metabolites causing liver cancer