Carcinogenic agents Flashcards
What are the two factors that can cause the consumption of carcinogen to contribute to the development of cancer
Dose and duration
How does carcinogens react chemically
They are reactive electrophiles, the bind to and react with DNA, leading to the development of tumor
What are the chemicals called that bind to DNA? What are their types
They are called DNA adducts. They can induce DNA mutations or they can lead to detoxication, in that case they are called non critical adducts
Name some enzymes that can be carcinogenic
- Estrogens 2. Adrogens 3. Goitrogenic agents (thyroids)
How does hormones cause cancer
- Excessive cell proliferation 2. There are some hormones that induce epigenetic changes that later contributes to the development of cancer
Name a bacterium that causes cancer and what kind of cancer does it cause
H. pylori causes gastric cancers
What parasite causes cancer
Plasmodium can lead to development of lymphoma
What viruses cause cancer
HPV can cause Kaposi Sarcoma. Hepatitis B and C can cause liver cancer
How does H. pylori exactly causes cancer
It leads to the excessive production of gastric juice, this leads to dissolving of the mucus membrane and leads to damaged cells. There is increased cell proliferation due to replace damaged cells. Also damaged cells cause release of cytokines and inflammation and reactive oxygen species that eventually leads to the development of cancer
What are the stages of carcinogenesis
Initiation phase - genetic change that is irreversible, phenotype is normal at this point Promotion (in this phase something happens) - clonal expansion like cell proliferation, results in phenotypic change, it is reversible, clears threshold, pre-neoplastic lesions Progression - the last stage - genotypic changes and phenotypic changes, complex genetic changes leading to genomic instability, irreversible, there is selection for one of the malignant phenotype
Know what he talked about in the slide that was about the interplay of environment, physiology and genetics
In this slide he explained the fact that a female mouse was exposed to a carcinogen. So when this mouse gave birth to offspring and breast fed them, only the daughters developed cancer and the males did not develop cancer. Additionally this experiment was repeated in a different strain of mice and no cancer was developed in the sons or in the daughters. At the end he stated that all the factors that we learned in pharamacogenetics about physiology, environment and genetics also apply to cancer.
What are the classifications of carcinogenic substances
- Carcinogenic 2A. Probably carcinogenic 2B. Possibly carcinogenic 3. Unclassified 4. Probably not carcinogenic
