Environmental Factors and Cancer Flashcards
List 5 environmental factors that contribute to cancer formation.
1 - Diet.
2 - Tobacco
3 - Alcohol.
4 - Infectious disease such as HPV.
5 - Pollution.
6 - Water contaminants.
7 - UV radiation.
8 - Medicine.
List 6 substances which contribute to air pollution.
1 - Particulate matter of 10 and 2.5 micrometers in diameter.
2 - Nitrogen dioxide.
3 - Sulphur dioxide.
4 - Ozone gas.
5 - Carbon monoxide.
6 - Polycyclic aromatic hydrocarbons (PAHs).
List 6 cellular effects induced by exposure to particulate matter.
1 - Sustained proliferative signalling.
2 - Cell death resistance.
3 - Angiogenesis induction.
4 - Activation of invasion and metastasis.
5 - Inflammation.
6 - Genome instability.
Define DNA adduct.
A form of DNA damage caused by covalent attachment of a substance to DNA.
List 3 pathways by which tobacco can cause cancer.
1 - Nicotine and tobacco carcinogens bind to receptors that trigger PI3K-Akt and PKA pathways, increasing angiogenesis and decreasing apoptosis.
2 - Tobacco carcinogens cause DNA adducts, causing mutations.
3 - Co-carcinogens of tobacco carcinogens trigger the PKC and AP1 pathways, enhancing carcinogenicity.
Define co-carcinogen.
A substance that promotes the effects of a carcinogen in the production of cancer.
List 3 cancers that are particularly more common in smokers than in non-smokers.
1 - Lung cancer.
2 - Oesophageal cancer.
3 - Pancreatic cancer.
List 4 group 1 carcinogens according to the IARC carcinogen classifications.
1 - Smoking.
2 - Exposure to solar radiation.
3 - Alcohol.
4 - Processed meats.
List 4 group 2a carcinogens according to the IARC carcinogen classifications.
1 - Emissions from high temperature frying.
2 - Steroids.
3 - Exposures working in hairdressing.
3 - Red meats.
List 4 group 2b carcinogens according to the IARC carcinogen classifications.
1 - Coffee.
2 - Gasoline.
3 - Welding fumes.
4 - Pickled vegetables.
Which type of cancer is most strongly associated with red meat intake?
Colorectal cancer.
Which type of cancer is most strongly associated with red meat intake?
Colorectal cancer.
List 3 foods that are anti-carcinogenic.
1 - Fibre.
2 - Fruit.
3 - Vegetables.
List 5 components of fruit and vegetables that are anti-carcinogenic.
1 - Fibre.
2 - Folate.
3 - Vitamin C.
4 - Vitamin E.
5 - Flavonoids.
List 4 reasons for the link between obesity and cancer progression.
1 - Cholesterol metabolites enhance metastatic proficiency by a process known as epithelial-to-mesenchymal transition.
2 - Obesity increases inflammasome activation in tumour-infiltrating myeloid cells, which drives increased IL-1 beta signalling (increasing mechanism #2 above). Adipocytes express VEGF-A in response to IL-1 beta, increasing tumour angiogenesis.
3 - Obesity increases myofibroblast content, which stiffens extracellular matrices and enhances cancer cell growth.
4 - Obesity causes an increase in monocyte expression of GM-CSF, promoting neutrophil expansion. Neutrophils then accumulate in the lung and promote growth of disseminated cancer cells.
What are crown-like structures?
- Dead adipocytes surrounded by macrophages.
- A hallmark of the proinflammatory response.
Describe the obesity-inflammation-aromatase axis.
- Obesity increases inflammation.
- Inflammation is associated with an increase in crown-like structures.
- Crown-like structures are associated with increased aromatase expression.
- Aromatase converts androgens into oestrogens.
- Oestrogens are associated with increased risk of cancer.
List 9 reasons that explain the link between increased alcohol consumption and increased cancer risk.
Chronic ethanol consumption increases:
1 - Production of acetaldehyde.
2 - Induction of oxidative stress.
3 - Conversion of procarcinogens to carcinogens.
4 - Induction of DNA hypomethylation.
5 - Induction of Gi alpha subunit proteins and Erk-MAPK signalling.
6 - Accumulation of iron and associated oxidative stress.
7 - Inactivation of BRCA1 tumour suppressor gene.
8 - Increased oestrogen responsiveness.
9 - Impairment of retinoic acid metabolism.
Which condition is caused almost exclusively by exposure to asbestos?
Pleural mesothelioma.
How does the proportion of cancers caused by lifestyle factors differ between men and women?
Why might this be?
- In men, the proportion of cancers caused by environmental factors is 45%, whereas in women it is 40%.
- This is mainly due to sex differences in smoking.
List 7 forms of prevention for cancer caused by lifestyle factors.
1 - Quitting smoking.
2 - Avoiding sunlight.
3 - Clean water supply.
4 - Chemoprevention.
5 - Anticancer vaccines.
6 - Healthy diet.
7 - Exercise.