233b chemical carcinogens

Question 1

what % of cancers are environmentally induced + aging? biggest contributors?

Answer 1

85% from environmental carcinogens + aging

environment: #1-diet, #2-tobacco

Question 2

aflatoxins (aspergillus) - organ and cancer?

Answer 2

liver

hepatocellular carcinoma

Question 3

alkylating agents (chemo drugs) - organ and cancer?

Answer 3

blood

leukemia/lymphoma

Question 4

aromatic amines (benzidine, 2-apthylamine) - organ and cancer?

Answer 4

bladder

transitional cell carcinoma

Question 5

arsenic - organs and cancesr?

Answer 5

liver –> angiosarcoma

lung –> lung cancer

skin –> squamous cell carcinoma

Question 6

asbestos - organ and cancer?

Answer 6

lung

bronchogenic carcinoma > mesothelioma

Question 7

carbon tetrachloride - organ and cancer?

Answer 7

liver

centrilobular necrosis, fatty change

Question 8

cigarette smoke - organs and cancer?

Answer 8

bladder –> transitional cell carcinoma

esophagus –> SCC/adenocarcinoma

kidney –> RCC

larynx –> SCC

lung –> SCC and small cell carcinoma

pancreas –> pancreatic adenocarcinoma

Question 9

ethanol - organ and cancer?

Answer 9

liver - HCC

Question 10

ionizing radiation - organ and cancer?

Answer 10

thyroid

papillary thyroid carcinoma

Question 11

nitrosamines (smoked foods) - organ and cancer?

Answer 11

stomach

gastric cancer

Question 12

radon - organ and cancer?

Answer 12

lung

lung cancer (2nd leading cause after smoking)

Question 13

vinyl chloride - organ and cancer?

Answer 13

liver

angiosarcoma

Question 14

polymerase chain reaction - purpose? steps?

Answer 14

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

Question 15

ames test - purpose? type of test? steps?

Answer 15

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)

Question 16

unscheduled DNA synthesis (UDS) test AKA

in vitro hepatocyte DNA repair assay - purpose? steps?

Answer 16

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

Question 17

carcinogenesis - stages?

Answer 17

Initiation

Promotion

Progression

Question 18

carcinogenesis - initiation

Answer 18

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

Question 19

carcinogenesis - promotion

Answer 19

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

Question 20

carcinogenesis - progression

Answer 20

Progression - additional genetic events –> malignant changes (undifferentiated neoplasia) that is irreversible; examples - inflammation, asbestos, benzene –> attract inflammatory cells