causes and risk factors Flashcards
(17 cards)
biggest risk factors for human cancer
age, tobacco, obesity, UV radiation, infections, alcohol
types of risk factors and what are they and examples
initiators=-mutagens/agents cause mutations, permanent damage in DNA sequence, single nucleotide changes, insertions, deletions, amplifications, chromosomes, rearrangements/losses/gains
-usually carcinogens (tobacco, UV, IR, chemotherapeutic drugs)
-causes cancer
promoters=doesnt directly damage DNA, stimulates cell proliferation of already mutated cells, increases chance a mutated cell turns into tumour, reversible if promoter removed, increase to rate of tumour progression
-inflammation, alcohol, chemical promoters, hormones dont need changes in gene sequence
-encourages cancer
what is HPV and what does it do
human papillomavirus
-inhibits cell progression by E7 inhibits RB1, which normally sequesters E2F transcription factors
-E6 targets P53 for degradation by promoting ubiquitination
where does helicobacter pylori live, what does it cause and what is it associated with
-lives in stomach, causes gastric and duodenal ulcers
-associated with gastric carcinomas and MALT lymphoma
examples of infectious animals
flatworms- causes bladder and bile duct cancer
tape worms
biggest avoidable cause of cancer
smoking
RAS mutation hotspots
codons 12, 13 and 61
where is benzopyrene diol epoxide found and what does it do
found in tobacco, highly carcinogenic, causes DNA adduct, guanine is misread as thymine leading to adenine being incorporated during DNA replication=mutation
what are mutagens
agents that causes change/mutations in DNA
list some environmental mutagens
-occupational chemicals/waste products (benzene, asbestos, aromatic amines)
-medical mutagens (chemo/radio therapy, imaging, xray)
-natural products (aflatoxin, herbal products, betel nuts)
-atmospheric particles
how can diet affect cancer
-fibre reduces bowel cancer risk
-fruit veg reduces mouth/ throat/lung cancer
-processed and red meats increases risk of bowel cancer
how can obesity affect cancer
-fat cells produce proliferative signals (e.g. estrogen, androgens, insulin, growth hormones)
-inflammatory signalling recruits immune cells
-abdominal fat is particularly harmful
how can alcohol affect cancer
-risk increases with intake
-alcohol converts into acetaldehyde which damages DNA
-leads to inflammation esp liver
-can cause mouth, larynx, oesophagus, breast, liver and bowel cancer
how can exercise affect cancer
-physical activity can reduce insulin and estrogen signalling=lower risks of breast and uterine cancer
-can increase GI transit, reducing contact w carcinogens indiet
-reduction in inflammation and obesity
-physically inactive can cause breast, bowel and womb cancer
how can hormones affect cancer
-steroid hormones can promote proliferation and survival
-conditions that reduce exposure to estrogens and progesterone are protective against breast and ovarian cancers
-breast cells more responsive to hormon changes
-breast feeding for >1 year reduces breast cancer risk
-pregnancy reduces breast and ovarian cancer risk
how can hormone replacement therapy affect cancer
-increases risk of breast, endometrial and ovarian cancer
-may reduce risk of colorectal cancer
how can hormonal contraception affect cancer
-increased lung, cervical ,breast cancer
-reduced colorectal, ovarian, lymphatic, endometrial cancers
