Neoplasia 3 Flashcards
(39 cards)
What is carcinogensis?
This is the causes of cancer which are both intrinsic and extrinsic.
Name some intrinsic causes of cancer
Genders, hormones, age, gender, ethnicity
What are extrinsic factors which cause cancer?
Environmental and lifestyle factors.
Is cancer prevalence increasing?
Yes, but only because people are living to be older and the older we are the higher risk because the more time we have had to pick up mutations.
What are the five major lifestyle and behavioural factors which can cause cancer?
Smoking, lack of exercise, alcohol and high BMI.
What are the three extrinsic carcinogens?
Radiation, chemicals and infections.
What is 2-napthylamine?
This is a carcinogen of the dye industry which taught us about cancer
What can be said about exposure to carcinogens and onset of cancer?
There is frequently a long delay between these two events.
What about total carcinogen dosage increases the risk of cancer?
If there is increased exposure then this leads to increased risk of cancer.
Why are some cancers only present in certain organs?
Some carcinogens show organ specificity in which they cause cancers.
Why are industrial chemicals and tobacco smoke most worried about in relation to cancer?
Due to dose response, this means that household cleaning products do not put us at a significant risk. These two factors do however.
What is important about the sequence of carcinogen exposure?
Different carcinogens can be initiators or promoters. This means that initiators need to be given first followed by promoters in order for cancer to form.
What is the difference between cellular effect of initiators or promoters?
Initiators are generally mutagens, and then promoters causes prolonged proliferation of the tissue.
What is promotion in terms of cancer?
This is monoclonal expansion of mutant cells.
What effect does a germ line mutation have on neoplastic cells?
If there is a germ line mutation then it is likely that this person will develop cancer at a younger age because they need to accumulate less mutations.
Name some forms of mutagenic chemical carcinogens.
Polycyclic aromatic hydrocarbons, alkylation agents, aromatic amines, N-nitroso compounds, natural products such as asbestos
What is a complete carcinogen?
This is both an initiator and a promoter.
What damage to cells does radiation cause? How?
It causes damage to DNA. This can be either direct causing strand breaks or altered bases or it can be indirect due to free radical production. Radiation strips electrons off atoms.
What is radon?
This is the most common radiation that all of us are exposed to. This leads to increased risk of skin cancer.
How can infections be carcinogenic?
Directly as it affects the genes in the cell, or indirectly as regeneration of the tissue following chronic inflammation acts as a promoter.
How is HPV linked to cervical carcinoma?
HPV expresses E6/7 which inhibit p53 and pRB and so there is no regulation of entry into the cell cycle.
What type of carcinogens are hepatitis B/C?
Indirect. They cause chronic liver cell injury and the regeneration acts as a promoter.
What is the two hit hypothesis?
Because we have 2 tumour suppressor genes, both need to be mutated for tumour formation and so we need 2 mutations.
Why are cancers more common in those with genetic mutations?
If someone has a genetic mutation, then they only need to acquire one more mutation and this is more likely than an individual acquiring 2 mutations.
