Flashcards in MOD - carcinogenesis + behaviours of tumours Deck (108)
what two types of meat can cause colorectal cancer?
- red meat
- processed meat
what carcinogens are workers exposed to in aluminium production, coal gasification, coke production, iron and steel industries?
eg cadmium and nickel
mining of hematite and uranium exposes miners to what carcinogen?
what sort of cancers have been reported among woodworkers\?
cancers of the sinonasal cavities and paranasal sinuses
what industry exposes workers to the carcinogens B-napthylamine and 4-aminobiphenyl?
what type of cancer is seen in workers in boot/shoe manufacture and repair?
what is EPIC?
The European Prospective Investigation into Cancer and Nutrition (EPIC) study is one of the largest cohort studies in the world, with more than half a million (521 000) participants recruited across 10 European countries and followed for almost 15 years. EPIC was designed to investigate the relationships between diet, nutritional status, lifestyle and environmental factors, and the incidence of cancer and other chronic diseases.
what are the 6 categories of human carcinogens?
Chemicals e.g. PAHs, nitrosamines
Infectious agents e.g. human papilloma virus, Helicobacter pylori
Radiation e.g. UV light, radon
Minerals e.g. asbestos, heavy metals
Like cadmium and nickel
Physiological e.g. oestrogen, androgens
Chronic inflammation – free radicals and growth factors
what are PAHs
Polycyclic aromatic hydrocarbons (PAHs) are a group of more than 100 different chemicals that are released from burning coal, oil, gasoline, trash, tobacco, wood, or other organic substances such as charcoal-broiled meat
they are carcinogens
what type of cancer does exposure to aflatoxin cause? and what is it?
a mold found on food products such as corn and peanuts, peanut butter
what 4 types of cancer does alcohol cause?
pharynx, larynx, oesophageal, liver
what type of cancer does asbestos cause?
(ie of the lung pleura)
what type of cancer do x-rays cause?
leukaemia (bone marrow)
what kind of cancer does oestrogen cause?
what 6 types of cancer does smoking cause?
lung, mouth, oesophagus, pancreas, kidney, bladder
what kind of cancer does HPV (human papilloma virus) cause?
what is a carcinogen?
any agent that significantly increases the risk of developing cancer
what are the 3 types of carcinogen?
- modify or damage dna (genotoxic)
- induce proliferation and DNA replication (non-genotoxic)
- initiate and promote
- eg UV light
what 2 steps does initiation of cancer (mutation induction) require?
- chemical modification of DNA
- replication of modified DNA and mis-incorporation by DNA polymerase
what are the two ways in which promoters contribute to carcinogenesis?
- by stimulating the 2 rounds of DNA replication required for mutation fixation
- by stimulating clonal expansion of mutated cells, which enables the accumulation of further mutations
what are the 3 stages of carcinogenesis?
why are you a lot more likely to get a basal cell carcinoma than a melanoma?
because cancer is directly related to levels of cell division
Basal cells and maelanocytes (produce melanin) are exposed to the same amount of uv light but, because basal cells replicate more in normal physiology, you are 10 fold more likely to get a basal cells carcinoma than a melanoma
This would support a hypothesis that cell division, and by inference DNA replication, is a significant risk factor for the development of cancer
what genetic change is associated with chronic myeloid leukaemia?
translocation on chromosome 22 (Philadelphia translocation)
what is aneuploidy?
Aneuploidy is the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes instead of the usual 46.
mutations which result in an over-activation in which genes can cause cancer?
activation of proto-oncogenes
mutations which result in an inactivation in which genes can cause cancer?
inactivation of tumour suppressor genes (TSGs)
what is a colloquial name for a common type of promoter sequence?
what does methylation of promotor sequences result in?
loss of gene expression of said gene
what are the two 'umbrella' ways that carcinogens can induce cancer?
- interact directly with DNA
(eg oxygen radicals, UV light, ionising radiation, nitrogen mustard)
- require enzymatic (metabolic) activation before they react with DNA
(eg polycyclic aromatic hydrocarbons - PAH, found in burnt organic products)