Cancer Flashcards
6 hallmarks of cancer
- Growth factor independence
- avoids apoptosis
- angiogenesis
- proliferate without limit
- loss of tumour suppression genes i.e insensitive to growth inhibitors
- metastasis
What is growth factor independence?
Cell loses it’s need to be stimulated by growth factors in order to enter cell cycle, so gain an oncogene. Get gain in function and proliferation, RAS, Bcr-ab1, myc, her2+
Define oncogene
A gene when. overexpressed/mutation can. cause cancer
What is insensitivity to growth inhibitors?
Loss of tumour suppression genes so cant control abnormal cell proliferation, p53, PRB, BRCA - cannot. detect. damage or initiate. repair/apoptosis
What is the ability to proliferate without limit?
Rebuild their telomers via overexpression of telomerase enzyme and thus they keep proliferating and never shorten
What is the avoidance of apoptosis?
they are resistant to apoptotic signals gained from a. gain in function (overexpressed pro-survival factors bcl2 so less. sensitive to apoptotic signals)
or a loss of function of pro-apoptotic factors e.g. p53
What is promotion of angiogenesis?
Secures a blood supply and blood vessel formation via secretion of angiogenic factors e.g. VEGF, FGF
What is invasion/metastases?
Where the malignant cells move, break away and spread to other cells and reach blood vessels. This is due to decreased expression. of cell adhesion molecules or secretion of proteases to break down the ECM.
usually do this in highly perfused tissues with high. blood d supply
what % of all cancer deaths are due to metastasis?
90%
How does. cancer kill?
Interferes with organ function. (blocks, obstructs, deprives it of nutrients).
also interferes with metabolic processes
What is a single mutation?
A single. property acquired but this is not enough to cause cancer, need all the hallmarks
what can cause mutations?
UV radiation, viruses, free radicals, chemials
What is the TNM scheme
identifies how far a tumour has progressed. - tumour, nodes, metastases
What are the cancers with best survival rates?
Testicular/prostate, breast
Melanoma in women.
What cancers have poor survival rates
stomach, oesophageal, lung, pancreas
What % of cancers are caused by infection?
18%
What are the hierarchy of aims in treatment of cancer
- cure
- remission
- symptom/palliation
- terminal care
What is palliation?
when cure no longer possible, look at palliation where there is relief of symptoms and prolongation of life in proportion to their chemo sensitivity.
What is the life expectancy for solid tumours with current treatment and expectancy for leukaemias/lymphomas with current treatments?
solid tumours 2-18months
Leukaemias/lymphomas - 5-8 years
What are the options for chemotherapy treatment in terms of approaches?
- Drugs with synergistic effects
- drugs that target different parts of the cell cycle
- alternating regimens with least effective first
What can chemo be used for?
- adjuvant therapy after surgery/radio
- neo-adjuvant therapy before surgery/radio
- widely disseminated/metastasised disease
- diffuse tumour e.g. leukaemia
- palliation
- some primary tumours e.g. hodgkins lymphoma
How is chemo given?
Treatment on an intermittent basis with the shortest possible time between treatments that allows recovery of the most sensitive normal tissue
What phase of the cell cycle does methotrexate blocks?
G1 phase - stops cells making the building blocks of DNA
what drugs can you do TPMT gene testing on to predict risk of bone marrow toxicity?
purine drugs. e.g. mercaptopurine
Why is paracetamol an issue in chemotherapy
anti-pyretic and can mask signs of fever (which is a sign of infection) and. patients are immunocompromised at. higher risk
