233b chemical carcinogens Flashcards
what % of cancers are environmentally induced + aging? biggest contributors?
85% from environmental carcinogens + aging
environment: #1-diet, #2-tobacco
aflatoxins (aspergillus) - organ and cancer?
liver
hepatocellular carcinoma
alkylating agents (chemo drugs) - organ and cancer?
blood
leukemia/lymphoma
aromatic amines (benzidine, 2-apthylamine) - organ and cancer?
bladder
transitional cell carcinoma
arsenic - organs and cancesr?
liver –> angiosarcoma
lung –> lung cancer
skin –> squamous cell carcinoma
asbestos - organ and cancer?
lung
bronchogenic carcinoma > mesothelioma
carbon tetrachloride - organ and cancer?
liver
centrilobular necrosis, fatty change
cigarette smoke - organs and cancer?
bladder –> transitional cell carcinoma
esophagus –> SCC/adenocarcinoma
kidney –> RCC
larynx –> SCC
lung –> SCC and small cell carcinoma
pancreas –> pancreatic adenocarcinoma
ethanol - organ and cancer?
liver - HCC
ionizing radiation - organ and cancer?
thyroid
papillary thyroid carcinoma
nitrosamines (smoked foods) - organ and cancer?
stomach
gastric cancer
radon - organ and cancer?
lung
lung cancer (2nd leading cause after smoking)
vinyl chloride - organ and cancer?
liver
angiosarcoma
polymerase chain reaction - purpose? steps?
amplifies desired fragment of DNA for dx
steps:
1) denature via heat
2) anneal during cooling w/ DNA primers to specific sequence
3) elongation - heat stable DNA polymerase replicates DNA following primers
4) repeat for amplification
5) Agarose gel electrophoresis - PCR products are separated by size (small travels farther) - compare against DNA ladder
ames test - purpose? type of test? steps?
in vitro testing for carcinogens
bacterial mutagenesis assay
see if bacteria can grow without histidine (mutation has lead to mutation that allows growth in medium which bacteria doesn’t usually grow)
unscheduled DNA synthesis (UDS) test AKA
in vitro hepatocyte DNA repair assay - purpose? steps?
test for carcinogens that damage DNA after metabolism
most carcinogens require metabolic activation (use rat hepatocytes) –> test if mutagen can cause DNA damage via measuring of uptake of H3-thymidine which is incorporated during repair process
carcinogenesis - stages?
Initiation
Promotion
Progression
carcinogenesis - initiation
Initiation - binds DNA (DNA adduct) and causes mutation that isn’t repaired in a single cell (failure of DNA repair); permanent; requires initiator which binds DNA and causes mutation
carcinogenesis - promotion
Promotion - initiated cell replicates normally and increases # (differentiated benign neoplasia), reversible; Promotors lead to progression (ROS, estradiol, DES, etc) – weakly carcinogenic on own and doesn’t bind DNA, can modify epigenetics
carcinogenesis - progression
Progression - additional genetic events –> malignant changes (undifferentiated neoplasia) that is irreversible; examples - inflammation, asbestos, benzene –> attract inflammatory cells
