What is cancer?

Question 1

Define cancer

Answer 1

a collection of diseases with the common features of uncontrolled growth and life threatening risks.

Question 2

Define proliferation

Answer 2

the process of cell growth and cell division leading to expansion of the cell population

Question 3

Define differentiation

Answer 3

when early cells i.e stem cells give rise to specialised cells

Question 4

define neoplasm

Answer 4

term used to describe new growth without characterising the growth

Question 5

define tumour

Answer 5

general term to describe abnormal growth, may be benign or malignant

Question 6

define malignant

Answer 6

feature of cancer cells to invade surrounding tissues

Question 7

define metastasis

Answer 7

where cancer cells escape to other regions of the bodyu

Question 8

define benign

Answer 8

a confined growth which is not malignant

Question 9

List some differences between benign and malignant growth

Answer 9

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.

Question 10

define carcinogenesis

Answer 10

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

Question 11

what is the core feature of cancer

Answer 11

uncontrolled proliferation

Question 12

define angiogenesis

Answer 12

the growth of new blood vessels in a cance r

Question 13

why might a tumour invoke an immune response?

Answer 13

it may be read as “foreign” by the body and cause an immune response

Question 14

what cancers are common in childhood?

Answer 14

eye cancers and certain leukaemia

Question 15

what are some lifestyle influences on cancer

Answer 15

diet, free radical generation, hormonal proliferation stimuli, carcinogens in cigarettes, occupational risks (factory or chemical exposure)

Question 16

what two cancers are common in the Western countries and what two cancers are more common in Asia (notably China)

Answer 16

Western: breast and prostate
China: cervix and stomach

Question 17

how are cancers and genes related

Answer 17

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

Question 18

define repressor gene, oncogene and proto oncogenes

Answer 18

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

Question 19

Why is cancer cell culture so difficult?

Answer 19

due to the genetic instability and phenotypic variations

Question 20

How does cancer make energy from sugar molecules within the tumour?

Answer 20

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

Question 21

what can be used to help identify causative agents in cancer?

Answer 21

molecular analysis of genes

Question 22

what do biochemical analysis and biochemical markers do

Answer 22

can provide additional info for identifying people who are at risk of cancer development

Question 23

What are the three categories of epidemiology

Answer 23

Descriptive, Analytical and Molecular

Question 24

Write a note on Descriptive Epidemiology and the types of info obtained from the data collected

Answer 24

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.

Question 25

Write a note on Analytical Epidemiology

Answer 25

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

Question 26

What carcinogens are tested for when examining the plasma of passive smokers

Answer 26

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

Question 27

Explain Molecular Epidemiology

Answer 27

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