What is cancer? Flashcards
Define cancer
a collection of diseases with the common features of uncontrolled growth and life threatening risks.
Define proliferation
the process of cell growth and cell division leading to expansion of the cell population
Define differentiation
when early cells i.e stem cells give rise to specialised cells
define neoplasm
term used to describe new growth without characterising the growth
define tumour
general term to describe abnormal growth, may be benign or malignant
define malignant
feature of cancer cells to invade surrounding tissues
define metastasis
where cancer cells escape to other regions of the bodyu
define benign
a confined growth which is not malignant
List some differences between benign and malignant growth
Benign have encapsulated edges, no metastasis, no invasion, low growth rate, normal nuclei, unusual to be life threatening.
Malignant have irregular and unencapsulated edges. Has metastasis, it invades, high grow rate, variable and irregular and usually is life threatening.
define carcinogenesis
the process by which cancer is generated (multi step mechanism) and is the result of accumulation of errors in vital regulatory pathways and uncontrolled proliferation
what is the core feature of cancer
uncontrolled proliferation
define angiogenesis
the growth of new blood vessels in a cance r
why might a tumour invoke an immune response?
it may be read as “foreign” by the body and cause an immune response
what cancers are common in childhood?
eye cancers and certain leukaemia
what are some lifestyle influences on cancer
diet, free radical generation, hormonal proliferation stimuli, carcinogens in cigarettes, occupational risks (factory or chemical exposure)
what two cancers are common in the Western countries and what two cancers are more common in Asia (notably China)
Western: breast and prostate
China: cervix and stomach
how are cancers and genes related
cancers are generated by mutations that occur in genes that have a role in controlling cell growth- changes in cell signalling pathways as a result of gene mutations result in uncontrolled growth
define repressor gene, oncogene and proto oncogenes
Repressor gene: gene whose protein product inhibits a cell function
Oncogene: a gene whose protein product contributes to carcinogenesis
Proto-oncogene: a gene in a normal cell that can become an oncogene due to a mutation
Why is cancer cell culture so difficult?
due to the genetic instability and phenotypic variations
How does cancer make energy from sugar molecules within the tumour?
Aerobic and anaerobic respiration. However when the cancer cells use glycolysis, it releases toxic lactic acid that may kill healthy cells to make room for more cancer cells. this is only effective when many cells use glycolysis
what can be used to help identify causative agents in cancer?
molecular analysis of genes
what do biochemical analysis and biochemical markers do
can provide additional info for identifying people who are at risk of cancer development
What are the three categories of epidemiology
Descriptive, Analytical and Molecular
Write a note on Descriptive Epidemiology and the types of info obtained from the data collected
Utilises records, cause of death and info about the person who died from cancer, such as their first detection of cancer, age, sex and race. death records can be used but incidence data is preferred. Descriptive epidemiology allows for different cancer rates to be calculated such as the changes of cancer rates over time.
Geographical incidence rates can also be collected in relation to race or location. ie japan has low melanoma and high stomach cancer rates. Migrating Chinese pops have increased breast and prostate cancer.
Write a note on Analytical Epidemiology
This is the comparison of two or more groups of people with different characteristics. A number called the relative risk is calculated which indicates the risk associated with a given factor.
Exposure example: comparison of lung cancer in smokers and non-smokers which defines smoking as a bad risk factor
Example 2: rates of breast cancer in parous women with nulliparous women, which shows having children reduces risk of breast cancers
What carcinogens are tested for when examining the plasma of passive smokers
Cotinine- a metabolite of nicotine which indicates exposure to this tobacco carcinogen - the level of this is related to the number of cigs smoked in particular households
Explain Molecular Epidemiology
This combines epidemiology methods with molecular analysis. For example, 2 mutations are seen in liver cancer patients in China; Hep B and a fungal toxin from peanuts. There is a diff in the mutation pattern generated by the two different carcinogens. Molecular analysis can help identify the difference between the two
