Cancer: Causes and Demographics Flashcards
explain how UV radiation leads to cancer
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
normal cells do not express what type of enzyme?
telomerase
normally when telomeres are shortened during replication…
cell division is stopped and the cell undergoes apoptosis
abnormally when telomeres are shortened…
telomerase is activated and telomeres are lengthened, replication continuous indefinitely and chromosomes do not get shorter
cancer cells expressing telomerase causes
indefinite replication
describe cancer stem cells
undifferentiated cells that become mutated, then acquire additional mutations initiating a cancerous tumor
if tumors contain CSCs it may have
unlimited proliferation
how do CSCs cause tumor recurrence
b/c they’re efficient at metastasis and chemo-resistance
who proposed normal blood stem cells accumulate rare mutation causing them to become cancerous
Irving Weissman (2005)
prove to Irving Weissman’s theory
- 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
what are 3 challenges to Irving Weissman’s theory?
- identify the mutation in several acute myeloid leukemia cells
- isolate and analyze rare, pre-cancerous stem cells
- determine which mutations were present in the normal stem cells
give an example of correlational data
as cigarette consumption increased so did the lung cancer death rate
what concept supports a suspected carcinogen as the cause for cancer?
the dose-response concept
what cancer is caused by ppl who drink and smoke?
oropharyngeal cancer
why is the relative risk of developing oropharyngeal cancer much much higher in ppl who are both heaving drinkers and smokers
b/c alcohol is a vasodilator which will dilate lung blood vessels increasing the exposure/absorption of cigar carcinogens
in cancer risk and environment, what environments had the highest mortality rates
tobacco and diet
why do southern state w/ higher sunlight intensity have higher cancer rates
the increase in elevation means the atmosphere is thinner increasing the sunlight intensity
what type of cancer was ID when sarcoma tissue was removed from a chicken
rous sarcoma virus
give an example of a proven human carcinogen that also causes cancer in humans
mustard gas (lung cancer)
give an example of some medications that can cause cancer and what type of cancer they cause
estrogens (a hormone) causing cancer in the breasts, uterus, and vagina
secondary contributors include
-inflammation
-obesity
how can inflammation be a secondary contributor?
bc post-inflammatory factors promote tumor growth
how can obesity be a secondary contributing factor to cancer
changes in gut microbiome can create DNA-damaging metabolites causing liver cancer
