Lecture 1 - introduction to cancer

Question 1

what is cancer ?

Answer 1

abnormal cell growth/ division (cell proliferation).
behave differently depending upon the cell type from which they originate. spreads to other regions of the body (metasis)

Question 2

what is benign?

Answer 2

benign is when the lumps or tumour are non cancerous.

Question 3

what are examples of malignant cancer?

Answer 3

skin cancers, colorectal cancer, and lung cancer

Question 4

who gets cancer and what are the incidences of getting cancer?

Answer 4

cancer incidence increases with age and more males than females get cancer

Question 5

what type of cells can become can cancerous?

Answer 5

nerve cells, skin cells, gut cells, red blood cells

Question 6

describe normal vs cancerous cell division

Answer 6

in normal cell division, cells divide and multiply form one cell. when there is cell damage there is no repair and leads to cell death or apoptosis of the damaged cell. there is a balance between new cell growth and cell death.

in cancer, there is loss of normal growth control. the damaged cell keeps dividing and mutating as the body does not recognise the , which accumulates into a cluster of damaged cells

Question 7

describe the scale of cell death and production

Answer 7

cell death dominates new cell growth

Question 8

what are signs and symptoms of cancer

Answer 8

early cancer has no symptoms

change in bowel habits or bladder functions

sores that do not heal

unusual bleeding or discharge

lumps or thickening of breast or other parts of the body

indigestion or difficulty swallowing

recent change in wart bor mole

persistent coughing or hoarseness

Question 9

what can cause cancer?

Answer 9

heredity, diet, hormones, smoking, radiation, viruses or bacteria, diet

Question 10

what causes cells to become cancerous?

Answer 10

non-lethal genetic damage lies at the heart of carcinogenesis. genetic damage acquired by the action of environmental agent, such as chemicals, radiation or viruses, or may be inherited in the germ line

Question 11

how can colorectal cancer come about?

Answer 11

separate mutational events occur over time.

Question 12

what are examples of chemical substances in cigarettes known to be carcinogenic?

Answer 12

arsenic, benzene, cadmium, nickel, 2-naphthylamine

Question 13

name cancer causing agents in the workplace

Answer 13

asbestos, construction workers, lung cancer

benzene, petroleum

Question 14

how do virus cause cancer

Answer 14

some of the viral genetic information carried in these nucleic acids is inserted into the chromosomes of the infected cell, and this causes the cell to become malignant

Question 15

where can we get ionising radiation from?

Answer 15

cosmic rays, fallout Chernobyl, radon gas, X-ray machines

Question 16

what are inherited condition that can increase the risk for cancer ?

Answer 16

xeroderma pigmentosum can cause skin cancer

film’s cancer can cause kidney cancer

familial adenomatous polyposis can cause colon/rectum cancer

BRCA1/2 can cause breast or ovarian cancer

Question 17

what are the target of DNA damage?

Answer 17

the growth promoting port-oncogenes

the growth inhibitory tumour suppressor genes

the genes that regulate programmed cell death, apoptosis- may be one or TS genes

the genes that produce proteins which are involved in DNA damage response and repair

Question 18

what are proto- oncogenes?

Answer 18

natural gene that regulates cell growth with the potential to become oncogenes

Question 19

what are oncogenes?

Answer 19

genes that code for mutant forms of normal signalling molecules that regulate and control cell growth: proliferation, differentiation and survival (protooncogenes)

Question 20

what genes can mutate to cause cancer and give an example of the process of this?

Answer 20

genes coding for:
growth factors

growth factor receptors

systolic transducers

nuclear transducers

growth factor bind to receptors on he cell surface which activate signalling enzymes inside the cell that, in turn, activate special proteins called transcription factors inside the cell’s nuclear, the activated transcription factors ‘turn on’ genes required for cell growth/ proliferation.

Question 21

what are oncoprotein?

Answer 21

oncogenes encode proteins called oncoprotein which resemble the normal products of port-oncogenes with the exception that oncoprotein are devoid of important regulatory elements and their production in the transformed cell does not depend on growth factors or other external signals.

Question 22

what are the sequence of events that characterise normal cell proliferation?

Answer 22

a) the binding o a growth factor to its specific receptor
b) transient and limited activation of the growth factor receptor –> activates several signal transduction proteins
c) transmission of the transducer signal across the cytosol to the nuclear via second messenger formation and/or translocation of addition accessory proteins
d) induction and activation of nuclear regulatory factors initiate DNA transcription
e) entry and progression of the cell into the cell cycle, resulting ultimately in cell division

Question 23

what does a normal cell require?

Answer 23

for a normal cell to grow it requires a signal which is usually a growth factor/ hormone whereas cancer cells just grow itself.

growth factor binds to the growth factor receptors, which bind to intracellular signalling pathway and activates transcription factors and makes gene induced

Question 24

what are tumour suppressor genes?

Answer 24

tumour suppressor egenes a re a firmly of normal evens that instruct cells to produce proteins that restrain cell growth and division. since tumour suppressor genes code for proteins that slow down cell growth and division, the loss of such proteins allows a cell to grow and divide in an uncontrolled fashion.

Question 25

what does it mean by tsgs are recessive

Answer 25

both copies of the Aegean need to be missing

Question 26

give a summary of normal cell division

Answer 26

normal cell division is regulated by tumour suppressor genes. protocol-oncogenes are stimulated which causes cell growth and proliferation.

Question 27

give a summary of ways cancer is caused

Answer 27

cancer due to oncogenes: protooncogenes are activated into oncogenes, which increases rate of cell growth and proliferation and leads to a malignant transformation

cancer due to the action of mutated tumour suppressor genes: protocol oncogenes causes cell growth and proliferation but there is loss or mutation of tumour suppressor genes.leads to malignant tumour

Question 28

what are defects in 3 types of DNA repair that contribute to different types of systems

Answer 28

mismatch repair, nucleotide excision repair and recombination repair