Lecture 1 - introduction to cancer Flashcards
what is cancer ?
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)
what is benign?
benign is when the lumps or tumour are non cancerous.
what are examples of malignant cancer?
skin cancers, colorectal cancer, and lung cancer
who gets cancer and what are the incidences of getting cancer?
cancer incidence increases with age and more males than females get cancer
what type of cells can become can cancerous?
nerve cells, skin cells, gut cells, red blood cells
describe normal vs cancerous cell division
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
describe the scale of cell death and production
cell death dominates new cell growth
what are signs and symptoms of cancer
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
what can cause cancer?
heredity, diet, hormones, smoking, radiation, viruses or bacteria, diet
what causes cells to become cancerous?
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
how can colorectal cancer come about?
separate mutational events occur over time.
what are examples of chemical substances in cigarettes known to be carcinogenic?
arsenic, benzene, cadmium, nickel, 2-naphthylamine
name cancer causing agents in the workplace
asbestos, construction workers, lung cancer
benzene, petroleum
how do virus cause cancer
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
where can we get ionising radiation from?
cosmic rays, fallout Chernobyl, radon gas, X-ray machines
what are inherited condition that can increase the risk for cancer ?
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
what are the target of DNA damage?
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
what are proto- oncogenes?
natural gene that regulates cell growth with the potential to become oncogenes
what are oncogenes?
genes that code for mutant forms of normal signalling molecules that regulate and control cell growth: proliferation, differentiation and survival (protooncogenes)
what genes can mutate to cause cancer and give an example of the process of this?
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.
what are oncoprotein?
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.
what are the sequence of events that characterise normal cell proliferation?
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
what does a normal cell require?
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
what are tumour suppressor genes?
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.
what does it mean by tsgs are recessive
both copies of the Aegean need to be missing
give a summary of normal cell division
normal cell division is regulated by tumour suppressor genes. protocol-oncogenes are stimulated which causes cell growth and proliferation.
give a summary of ways cancer is caused
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
what are defects in 3 types of DNA repair that contribute to different types of systems
mismatch repair, nucleotide excision repair and recombination repair
