What are the steps of classical genotoxic carcinogenesis?
Why is it difficult to make human models for carcinogens?
I really hope you just know this.... It should pretty much be self explanatory.... Hey I'll give you ten bucks to expose yourself to these compounds and I wanna see how fast you get cancer... I always wondered what Miles' mother did during her pregnancy with Miles
What is occurring in the promotion stage of carcinogenesis?
Phenotypic changes caused by, or leading to, clonal expansion that yields pre-neoplastic lesions. This is reversible
What are carcinogens?
Agents that damage DNA, increasing the risk for cancer. Important ones are chemical, oncogenic viruses and radiation.
Explain the variability in individual susceptibility to carcinogens?
Susceptibility requires an interplay of environmental, physiological and genetic factors. Sometime males will develop cancers that females wont and vice versa. Also having a susceptible strain to yield a phenotypic characteristic is also necessary.
What is occurring in the progression stage of carcinogenesis?
Complex genetic changes leading to genomic instability. Selection of a malignant phenotype. This stage is irreversible
Cancer formation is initiated by?
Damage to DNA of stem cells, which overcomes DNA repair mechanisms but is not lethal to the cell
How have viruses been linked to cancer?
Viruses can release their DNA and incorportate into the host genome. This can lead to viral promoters activating c-onc leading to inappropriate growth of factors. Viruses can also contain v-onc which induces altered growth.
What is occurring in the initiation stage of carcinogenesis?
Irreversible genetic changes but cells are phenotypically normal
What is the process of hormonal carcinogenesis?
Hormonal stimulation leading to excessive proliferation which can lead to accumulation of DNA errors. Continued proliferation of these cells with DNA errors can then lead to cancer.
DNA mutations will eventually disrupt what leading to what?
Key regulatory systems allowing for tumor promotion (growth) and progression (spread).
UV light can lead to what type of DNA damage?
Thymidine dimers; this can lead to altered base pairing and information processing
What is the basic overview for carcinogenic studies?
Expose to carcinogen, change a few things about exposure length and concentration, and watch cancer develop.
Ionizing radiation can lead to what?
Oxidized bases (8-OHdG) and strand breaks
How has H. pylori been linked to cancer?
In response to infection there is proliferation to replace the damaged cells. Along with this infiltration of inflammatory cells releasing cytokines, growth factors and Reative Species (ROS and RNS) can affect DNA leading to cancer.